Relevant bibliographies by topics / Cold Molecule

Academic literature on the topic 'Cold Molecule'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Cold Molecule"

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Campbell, Wesley C., Cheong Chan, David DeMille, John M. Doyle, Gerald Gabrielse, Yulia V. Gurevich, Paul W. Hess, et al. "Advanced cold molecule electron EDM." EPJ Web of Conferences 57 (2013): 02004. http://dx.doi.org/10.1051/epjconf/20135702004.

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Wang, Dajun. "A versatile cold-molecule collider." Nature 572, no. 7768 (August 2019): 180–81. http://dx.doi.org/10.1038/d41586-019-02356-3.

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Gandhi, Suketu R., Qi Xun Xu, Thomas J. Curtiss, and Richard B. Bernstein. "Oriented molecule beams: focused beams of rotationally cold polar polyatomic molecules." Journal of Physical Chemistry 91, no. 21 (October 1987): 5437–41. http://dx.doi.org/10.1021/j100305a011.

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Ishkhanyan, A., R. Sokhoyan, B. Joulakian, and K. A. Suominen. "Rosen–Zener model in cold molecule formation." Optics Communications 282, no. 2 (January 2009): 218–26. http://dx.doi.org/10.1016/j.optcom.2008.10.008.

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Pawlak, Mariusz, Yuval Shagam, Edvardas Narevicius, and Nimrod Moiseyev. "Adiabatic theory for anisotropic cold molecule collisions." Journal of Chemical Physics 143, no. 7 (August 21, 2015): 074114. http://dx.doi.org/10.1063/1.4928690.

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Suzuki, H., M. Ohishi, M. Morimoto, N. Kaifu, P. Friberg, W. M. Irvine, H. E. Matthews, and S. Saito. "Recent Observations of Organic Molecules in Nearby Cold, Dark Interstellar Clouds." Symposium - International Astronomical Union 112 (1985): 139–44. http://dx.doi.org/10.1017/s0074180900146443.

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We report recent investigations of the organic chemistry of relatively nearby cold, dark interstellar clouds. Specifically, we confirm the presence of interstellar tricarbon monoxide (C3O) in Taurus Molecular Cloud1 (TMC-1); report the first detection in such regions of acetaldehyde (CH3CHO), the most complex oxygen-containing organic molecule yet found in dark clouds; report the first astronomical detection of several molecular rotational transitions, including the J=18−17 and 14−13 transitions of cyanodiacetylene (HC5N), the 101−000 transition of acetaldehyde, and the J=5−4 transition of C3O; and set a significant upper limit on the abundance of cyanocarbene (HCCN) as a result of the first reported interstellar search for this molecule.
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Fisch, L., and G. Kurizki. "Free matter wavepacket teleportation via cold-molecule dynamics." Europhysics Letters (EPL) 75, no. 6 (September 2006): 847–53. http://dx.doi.org/10.1209/epl/i2006-10205-7.

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Ishkhanyan, A. M., B. Joulakian, and K. A. Suominen. "Two strong nonlinearity regimes in cold molecule formation." European Physical Journal D 48, no. 3 (June 13, 2008): 397–404. http://dx.doi.org/10.1140/epjd/e2008-00117-0.

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CHIN, CHENG, ANDREW J. KERMAN, VLADAN VULETIĆ, and STEVEN CHU. "CONTROLLED ATOM-MOLECULE INTERACTIONS IN ULTRACOLD GASES." Modern Physics Letters A 18, no. 02n06 (February 28, 2003): 398–401. http://dx.doi.org/10.1142/s0217732303010557.

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We observe and study the dynamic formation of cold Cs 2 molecules near collision Feshbach resonances in a cold cesium sample. The resonance Iinewidth is as low as E/h = 5 kHz , or equivalently, 10-11 eV. We suggest that few-atom, interaction effects can be studied in a 3D optical lattice where several atoms can be confined and isolated in an optical cell, which allows exquisite control of the atomic density and the interaction cross section.
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Horchani, R. "Cold molecules: Formation, ro-vibrational cooling and electronic conversion." International Journal of Modern Physics B 30, no. 14 (June 2, 2016): 1630010. http://dx.doi.org/10.1142/s0217979216300103.

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The possibility of controlling all the motion as well as the internal quantum state of a sample of molecules is a long term goal in the cold molecules field. Although many different techniques have been used to produce ultra-cold molecules, in this paper, we will concentrate on the optical pumping technique successfully used to achieve rotational and vibrational cooling of Cs2molecules. We will review the different photo-association schemes for molecule formation, the detection schemes through photoionization, the ro-vibrational cooling into a single level and finally the electronic conversion. In addition, we will present a theoretical model for both ro-vibrational cooling and electronic conversion that can be used for the preparation of different experiments.
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Dissertations / Theses on the topic "Cold Molecule"

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Steer, Edward. "Development and characterisation of a cold molecule source and ion trap for studying cold ion-molecule chemistry." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:13c3a622-ba78-4a53-902c-666ec461f708.

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A novel apparatus, combining buffer-gas cooling, electrostatic velocity selection and ion trapping, has been constructed and characterised. This apparatus is designed to investigate cold ion-molecule chemistry in the laboratory, at a variable translational and internal (rotational) temperature. This improves on previous experiments with translationally cold but rotationally hot molecule sources. The ability to vary the rotational temperature of cold molecules will allow for the experimental investigation of post-Langevin capture theories.
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Deb, Nabanita. "Towards cold state-selected ion-molecule reactions." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:1a3899d3-7476-49ac-8f4b-3c0e7a7e8680.

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In recent years there has been much progress in the field of cold and ultracold molecular physics and a variety of experimental techniques for producing cold matter now exist. In particular, the generation of trapped molecular ions at mK temperatures has been achieved by sympathetic-cooling with laser-cooled atomic ions. By implementing schemes to selectively prepare and control the internal quantum state of molecular ions, and developing detection techniques, it will be increasingly possible to study cold state-selected chemical collisions in an ion-trap. Most molecular species produced in a selected rovibrational state have a lifetime of a few seconds, before the population is redistributed across numerous rovibrational states by interaction with the ambient blackbody radiation (BBR). Consequently, the investigation of state-selected reaction dynamics at low temperatures in experiments where long time scales (minutes to hours) are required, is hindered. This thesis looks into developing strategies that maintain state selection in molecular ions, allowing one to observe state-selected reactions in cold environments, in particular the state-selected reaction between C2H+2 and ND3. Examining reactive ion molecule collisions under cold conditions provides insight into fundamental reaction dynamics, which are thermally averaged out at higher temperatures. A theoretical model is used to investigate laser-driven, blackbody-mediated, rotational cooling schemes for several 1Σ and 2Π diatomic species. The rotational cooling is particularly effective for DCl+ and HCl+, for which 92% and >99% (respectively) of the population can be driven into the rovibrational ground state. For the other systems a broadband optical pumping source is found to enhance the population that can be accumulated in the rovibrational ground state by up to 29% more than that achieved when exciting a single transition. The influence of the rotational constant, dipole moments and electronic state of the diatomics on the achievable rotational cooling is also studied. This approach is extended to consider the BBR interaction and rotational cooling of a linear polyatomic ion, C2H+2, which has a 2Π electronic ground state. The (1-0) band of the ν5 cis-bending mode is infrared active and strongly overlaps the 300 K blackbody spectrum. Hence the lifetimes of state-selected rotational levels are found to be short compared to the typical timescale of ion trapping experiments. Laser cooling schemes are proposed that could be experimentally viable, which involves simultaneous pumping of a set of closely spaced Q-branch transitions on the 2Δ5/2-2Π3/2 band together with two 2Σ+– 2Π1/2 lines. It is shown that this should lead to >70% of total population in the lowest rotational level at 300 K and over 99% at 77 K. In order to identify states of the acetylene ion that could be trapped sufficiently long enough for state-selected reactions in the ion trap with decelerated ND3, the theoretical work has been complemented by experimental investigations into the production of C2H+2 in selected states, and ion trapping of the same using sinusoidal and digital trapping voltages. Appropriate (2+1) REMPI (Resonance Enhanced Multiphoton Ionization) schemes are used to produce C2H+2 in different quantum states, with (1+1) Resonance Enhanced Multiphoton Dissociation (REMPD) employed to detect the ion thus produced. The concept of digital ion trapping for ejection onto MCPs is introduced. A comprehensive comparison between sinusoidal and digital trapping fields has been performed with respect to trap depth and stability regions. Programs have been developed to calculate the stability regions for different ions under varying experimental conditions. The trap depth has been derived for both digital and sinusoidal trapping fields. It is observed that as τ increases, the trap depth of a digital trap increases. For τ = 0.293, the trap depth and stability diagram for both sinusoidal and digital trapping fields would be equivalent. The trap depth at which the sinusoidal trap operates experimentally in our research group is ~1.36 eV. In contrast, the experimental parameters at which the digital trap operates generates a trap depth of 1.21 eV. Ca+ Coulomb crystals have been formed, stably trapped and stored for extended periods of time in both sinusoidally and digitally time-varying trapping fields. The sympathetic cooling of a diverse range of ions into Ca+ Coulomb crystals is demonstrated, again using both sinusoidal and digital trapping fields. Mass spectrometric detection of ionic reaction products using a novel ejection scheme has been developed, where ejection is achieved by switching off the trapping voltage and converting the quadrupole trap into an extractor-repeller pair by providing the ion trap electrodes with appropriate ejection pulses. This technique is developed using a digital trapping voltage rather than the sinusoidal trapping voltage, as ejection with sinusoidal trapping voltages is not clean (resonance circuitry used in the electronics induces ringing after switching off the trapping voltage). Coulomb crystals, both pure Ca+ and multi-component crystals, are ejected from the ion trap and the TOF trace obtained is recorded on an oscilloscope. When the integrated, base-line subtracted TOF peak is plotted against the number of ions in a Ca+ crystal and sympathetically-cooled Ca+ – CaF+ crystal, a linear relationship is obtained. This technique is found to be well mass-resolved, with the signal arising from CaOH+ (57 amu) and CaOD+ (58 amu) resolvable on the TOF trace. This technique would enable one to monitor a reaction in a Coulomb crystal where the reactant and product species are both either lighter or heavier than calcium, such as the reaction between C2H+2 and ND3, something which has not been previously possible. It is, also, potentially a very important technique for reactions with many product channels.
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Pollum, Laura L. "Digital ion trap mass spectrometry for cold ion-molecule chemistry." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:18c6451d-d247-4384-9257-f8864e038343.

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A promising new approach for studying cold ion-molecule chemical reactions is the combination of laser- or sympathetically-cooled trapped ions and slow-moving molecules from a cold molecule source, such as a quadrupole velocity selector or a Stark decelerator. Previous reaction studies using trapped atomic ions and slow molecules from a quadrupole velocity selector were able to reach average collision energies as low as 1 K. However, the guided molecules had an approximately room temperature rotational energy distribution, so the reactions studied were not truly cold. Thus, a new molecular source for producing translationally and rotationally cold molecules utilizing buffer gas cooling and quadrupole velocity selection was constructed by K. Twyman and characterized for use in cold reaction studies. This new source of cold molecules is referred to as the buffer gas guide. A new ion trap has been designed and built for use with the existing buffer gas guide. The new ion trap apparatus is compact and mechanically compatible with this new guide. It uses a linear Paul ion trap with cylindrical electrodes to trap ions. Two optical axes (one axial and one radial) enable efficient cooling of small ion crystals. A field-free time-of-flight tube and ion detection assembly are also incorporated into the apparatus. A new technique for determining the mass and quantity of trapped ions has also been developed, termed digital ion trap mass spectrometry. The new technique uses a digital RF waveform to trap ions before ejecting the ions radially from the trap using an ejection pulse applied to the trap electrodes. The ions are then detected after free flight along a time-of-flight tube. This technique was characterized by ejecting crystals of various sizes and compositions: Ca+ only, Ca+/CaF +, Ca+/CaOH +/CaOD+, and Ca+/NH +3 /NH +4 /H3O+. A linear relationship between the number of ions ejected (determined by comparing experimental and simulated crystal images) and the integral of the time-of-flight peak was observed for Ca+ and Ca+/CaF +. All mass peaks were resolved. Simulations of the trapped ions and their trajectories through the time-of-flight tube were also performed, and excellent agreement between the simulated and experimental mass resolution was observed. Progress towards combining the buffer gas guide with the previously independent ion trap is also presented. It is anticipated that the combined buffer gas guide ion trap apparatus will enable the study of ion-molecule reactions at low temperatures with translationally and rotationally cold molecules. It is anticipated that the new digital ion trap mass spectrometry technique will simplify the study of reactions when multiple product ions whose masses are separated by only 1 AMU are formed. A new ion trap has been designed and built for use with the existing buffer gas guide. The new ion trap apparatus is compact and mechanically compatible with this new guide. It uses a linear Paul ion trap with cylindrical electrodes to trap ions. Two optical axes (one axial and one radial) enable efficient cooling of small ion crystals. A field-free time-of-flight tube and ion detection assembly are also incorporated into the apparatus. A new technique for determining the mass and quantity of trapped ions has also been developed, termed digital ion trap mass spectrometry. The new technique uses a digital RF waveform to trap ions before ejecting the ions radially from the trap using an ejection pulse applied to the trap electrodes. The ions are then detected after free flight along a time-of-flight tube. This technique was characterized by ejecting crystals of various sizes and compositions: Ca+ only, Ca+/CaF+, Ca+/CaOH+/CaOD+, and Ca+/NH+3/NH+4/H3O+. A linear relationship between the number of ions ejected (determined by comparing experimental and simulated crystal images) and the integral of the time-of-flight peak was observed for Ca+ and Ca+/CaF+. All mass peaks were resolved. Simulations of the trapped ions and their trajectories through the time-of-flight tube were also performed, and excellent agreement between the simulated and experimental mass resolution was observed. Progress towards combining the buffer gas guide with the previously independent ion trap is also presented. It is anticipated that the combined buffer gas guide ion trap apparatus will enable the study of ion-molecule reactions at low temperatures with translationally and rotationally cold molecules. It is anticipated that the new digital ion trap mass spectrometry technique will simplify the study of reactions when multiple product ions whose masses are separated by only 1 AMU are formed.
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Oldham, James Martin. "Combination of a cold ion and cold molecular source." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:ef33adcb-609a-4329-b4d8-aca8a1c48661.

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This thesis describes the combination of two sources of cold atomic or molecular species which can be used to study a wide range of ion-molecule reactions. The challenges in forming these species and in determining the fate of reactive events are explored throughout. Reactions occur in a volume within a radio-frequency ion trap, in which ions have previously been cooled to sub-Kelvin temperatures. Ions are laser-cooled, with migration of ions slowed sufficiently to form a quasi-crystalline spheroidal structure, deemed a Coulomb crystal. Fluorescence emitted as a consequence of laser-cooling is detected; the subsequent fluorescence profiles are used to determine the number of ions in the crystal and, in combination with complementary simulations, the temperature of these ions. Motion imparted by trapping fields can be substantial and simulations are required to accurately determine collision energies. A beam of decelerated molecules is aimed at this stationary ion target. An ammonia seeded molecular beam enters a Stark decelerator, based on the original design of Meijer and co-workers. The decelerator uses time-varying electric fields to remove kinetic energy from the molecules, which exit at speeds down to 35 m/s. A fast-opening shutter and focussing elements are subsequently used to maximise the decelerated flux in the reaction volume while minimising undecelerated molecule transmission. Substantial fluxes of decelerated ammonia are obtained with narrow velocity distributions to provide a suitable source of reactant molecules. Combination of these two techniques permits studies of reactions between atomic ions and decelerated molecules that can be entirely state-specific. Changes in the Coulomb crystal fluorescence profile denote changes in the ion identities, the rate of these changes can be used to obtain rate constants. Determination of rate constants is even possible despite the fact that neither reactant nor product ions are directly observed. This work has studied reactions between sympathetically cooled Xe+ ions and guided ND3 and has obtained data consistent with prior studies. Determination of reactive events is complicated if ion identities can change without affecting the fluorescence profile, or if multiple reaction channels are possible. A range of spectroscopic techniques are discussed and considered in regards to determining rate constants and product identities. Pulsed axial excitation of trapped ions can follow rapid changes in average ion weights and subtle changes for small crystals. Time-of-flight mass spectrometry is also demonstrated using the trapping electrodes and is suitable for discrimination of ions formed within the trap.
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Hanna, Thomas Mark. "Dynamics of Feshbach molecule production." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:676c8932-9c30-4776-a264-67405fe61c0c.

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The variation of a magnetic field in the vicinity of a zero-energy resonance allows highly vibrationally excited molecules (‘Feshbach molecules’) to be produced from an ultracold atomic gas. In this thesis, we study the dynamics of this process. We begin by studying the dissociation of Feshbach molecules, showing that in the limit of a sudden jump the shape of the spectrum of dissociated atoms can act as a probe of the zero-energy resonance. For some resonances, such jumps are within reach of current experiments. We also study the intermediate region between sudden jumps and asymptotically wide, linear ramps. It is shown from a precise derivation how the latter limit leads to a universal spectrum with a shape independent of the implementation of the two-body physics, provided that the near-resonant scattering properties are correctly modelled. We then turn to the dynamics of Feshbach molecule production from thermal and condensed gases. Our microscopic quantum dynamics approach includes the exact twobody evolution as an input to the many-body calculations. We show that in the long-time limit, and the Markov limit for the interactions, the non-Markovian Boltzmann equation (NMBE) we derive for the one-body density matrix reduces to the normal Boltzmann equation. In the limit of short times and small depletion of the atomic gas, the molecule production efficiency can be calculated by thermally averaging the two-body transition probability density. This thermal averaging technique is applied to studies of the formation of Feshbach molecules using a magnetic field modulation that is near-resonant with the molecular bound state energy. The continuum is shown to have a significant effect on both the dynamics and efficiency of this process. We examine the dependence of the molecule production efficiency on the duration, amplitude and frequency of the modulation, as well as the temperature and density of the gas. This method of producing molecules is effective for a wide range of bound state energies, but requires sufficient variation of the two-body energy levels with magnetic field. Lastly, we implement the NMBE for the case of a fast linear ramp across a Feshbach resonance. The solution of this equation is made feasible by including a large part of the required computation in the kernel, which is calculated in advance. The NMBE allows predictions of the molecule production efficiency which go beyond the thermal averaging technique by accounting for the depletion and rethermalisation of the continuum. In the limit of small depletions, the two approaches give the same results. As the depletion increases, the two approaches differ due to many-body effects limiting the maximum possible molecule production efficiency. We have observed this in our simulations by considering higher-density gases. We have therefore shown the suitability and practicability of this beyond mean-field approach for application to further problems in the production of Feshbach molecules from ultracold gases.
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Gingell, Alexander David. "Applications of Coulomb crystals in cold chemistry." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:3b93832d-b9eb-49e1-b4a4-1bb43d7c9c00.

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This thesis describes the study of a range of ion-molecule reactions at very low collision energies using a newly developed experimental technique which involves the reaction of velocity-selected beams of translationally cold neutral molecules with very low kinetic energy ion ensembles. These studies have been enabled by the construction of a new apparatus for trapping and laser-cooling gas phase atomic ions (40Ca⁺). The laser-cooling process results in the formation of ordered, low kinetic energy, lattice-like ion structures, also known as "Coulomb crystals". The properties of single and multicomponent Coulomb crystals (which may also involve molecular ions), and their manipulation via modulation of the applied fields, are explored experimentally and with the use of molecular dynamics simulations. Variations in the laser-cooling parameters are shown to result in different steady-state populations of the electronic states of 40Ca⁺ involved with the laser cooling cycle, and these are modelled within an appropriate theoretical framework. The imaging of 40Ca⁺ fluorescence as a function of time allows the study of various ion-molecule reactions at collision energies around 300 K, with single ion sensitivity. These reaction studies are extended to low-temperature (collision energies close to 1 K), by combination of the ion trap apparatus with a bent quadrupole guide velocity-selector. Ion-molecule collision energies are shown to be variable over a short range through a change in the quadrupole guide voltage, or the ion trapping parameters; the effect of these modulations on the rate constant is explored for Ca⁺ + CH₃F. Bimolecular rate constants for the reactions of 40Ca⁺ with CH₃F, CH₂F₂ and CH₃Cl have been determined for a range of 40Ca⁺ state populations, allowing resolution of the global rate contributions from the ground and combined excited states. These results are analysed in the context of capture theories and ab initio electronic structure calculations. In each case, suppression of the ground state rate constant is explained by the presence of either a submerged or real barrier on the ground state potential surface. Rates of reaction from the combined excited states are generally found to be in line with capture theories, and in some cases variation is found between the high and low collision energy regimes. Molecular product ions generated in these experiments have been shown to be sympathetically-cooled into the crystal structure, and subsequently identified through resonance-excitation mass spectrometry. Molecular ions were also produced by multiphoton laser ionisation of a thermal background gas of OCS molecules. An ion-molecule reaction involving a molecular ion, that of charge transfer between OCS⁺ and ND₃, has been studied at a collision energy near 1 K for the first time using sympathetically-cooled OCS⁺ and velocity-selected ND₃. These experiments illustrate the generality of the techniques described herein, and should lead to many possibilities for future studies.
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Twyman, Kathryn S. "Electrostatic extraction of buffer-gas-cooled beams for studying ion-molecule chemistry at low temperatures." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:583d8060-5570-401d-a8f8-ef5751cfebbb.

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This thesis describes the design, construction, operation, and characterisation of an experimental apparatus that produces a source of internally cold, slow molecules that can be used for studying ion-molecule reactions at low temperatures. The apparatus combines buffer-gas cooling with a bent quadrupole velocity selector to cool both the translational and rotational degrees of freedom of the molecules. A cold cell (6 K) is filled with a buffer gas, such as helium, that exhibits sufficiently high vapour pressure for cryogenic applications. Hot molecules (150 to 300 K) enter the cell and thermalise with the buffer gas through collisions. Molecules are subsequently loaded into an electrostatic quadrupole guide, which acts as a velocity filter; only translationally cold polar molecules are guided around the bend. Using a buffer-gas-cooled source of molecules for electrostatic velocity selection, rather than a 300 K effusive source, yields a rotationally cold sample, with J ≤ 3. This rotational selectivity will enable the dependence of reaction cross sections on the reactant rotational state to be examined. Mass spectrometry is used to characterise cold molecular beams of ND3 and CH3F, while (2+1) REMPI spectra are recorded for the ammonia isotopologues. The peak velocity of guided ND3 is 75.86(0.70) ms-1 for standard conditions in a 6 K helium buffer gas cell (1.0 sccm ND3 flow rate, 0.6 mbar helium inlet pressure, ± 5 kV voltage). This corresponds to a peak kinetic energy of 6.92(0.13) K. (2+1) REMPI spectroscopy of the B1E''(v2'=5) ← X(1) transition enabled the rotational state distribution of guided ammonia molecules to be established. PGOPHER simulations of the experimental spectra suggest a rotational temperature of 10 K for ND3 molecules (from a 6 K helium buffer gas cell). The extent of translational and rotational cooling can be controlled by varying the molecular and buffer gas densities within the cell, by changing the temperature of the buffer gas cell (we can operate at 6 K or 17 K), or by changing the buffer gas. The translational temperature of guided ND3 is similar in a 6 K helium and 17 K neon buffer gas cell (peak kinetic energies of 6.92(0.13) K and 5.90(0.01) K, respectively) because the heavier neon gas has a slightly lower thermal velocity at 17 K than helium does at 6 K. Despite similar translational temperatures, the rotational temperature of guided ND3 is lower for molecules exiting the 6 K helium cell compared to the 17 K neon buffer gas cell (10 K and 15 K, respectively). The 6 K helium and 17 K neon buffer gas cells provide an excellent opportunity to investigate the effect of rotational cooling on branching ratios and reaction rates in low temperature ion-molecule reactions. The buffer gas cell and velocity guide described in this work will be combined with a linear Paul ion trap, to facilitate the study of cold ion-molecule reactions.
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Kas, Milaim. "Cold chemistry of molecular anions: a theoretical investigation in the context of hybrid trap experiments." Doctoral thesis, Universite Libre de Bruxelles, 2018. https://dipot.ulb.ac.be/dspace/bitstream/2013/279061/4/main.pdf.

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Hybrid trap experiments are set-ups that allow to study the interaction between ions and atoms in cold controlled environment. In such context, molecular anions present specific theoretical and experimental interests and challenges. In this work, we have used extensive \textit{ab initio} methods to investigate several collisional anionic systems: (1) M + OH$^{-}$ (where M are alkali or alkaline earth atoms), (2) Rb and H + OH(H$_{2}$O)$_{n}^{-}$ (with $n=0,1,2,3,4$) and (3) Rb and Li + C$_{2}^{-}$. Several molecular properties such as vertical detachment energies or electroaffinities, optimized structures, harmonic frequencies, potential energy curves or surfaces, etc have been calculated using high level quantum chemistry approaches. The results have been used to make predictions on the related reactivity in low energy regime. We emphasis on electronic detachment processes by carefully analysing the difference between the neutral and anionic potential energy surface. The Rb + OH$^{-}$ system is currently under experimental investigation. Therefore, a detailed study of its reactivity is carried out in the present work. We have analysed the different reactive channels arising from both collision involving the ground state and first electronic excited state of Rb. Using our calculated potentials and a capture model based dynamics, we have extracted cross sections and rate constants. Comparison with other alkali and earth alkaline atoms are made. Hydrated hydroxide cluster anions are planned by the experimental group as upcoming studied systems. We present here our preliminary results on the possible outcome when considering collisions with Rb and we discuss their implications for hybrid trap experiments. We make comparison with H as a colliding partner and consider our results in the context of astrochemistry. Finally we propose the C$_{2}^{-}$ molecular anion as an alternative to OH$^{-}$. Its interaction and reactivity with Rb and Li are investigated and the results are used to motivate our suggestion. Furthermore, for the Rb+OH$^{-}$ and Rb+C$_{2}^{-}$ system, we have also investigated the effect of a non-thermal collision energy distribution on the rate constants. At last, in light of the discussions related to each topic, general conclusions on the use of molecular anions in hybrid trap experiments are drawn.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Hartl, Hugo M. "Modification of small-molecule organic thin films using energetic beams and plasma." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/129526/9/Hugo%20Hartl%20Thesis.pdf.

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This project investigated directed energy techniques for modifying organic films. These techniques show great promise for creating materials with unique, tailored properties. In this work, ion and electron beams were used to fabricate spatially-defined polymer features in nanometre-scale film of small molecules. An alternative pathway to the direct on-surface fabrication of polymer surface coatings was also investigated and showed that a room temperature, atmospheric pressure plasma can facilitate coupling of small molecules at a catalytic surface. In all cases, it was possible to control the optical properties, chemistry, solubility and hardness of the polymer films by varying the processing parameters.
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Newell, Catherine A. "INELASTIC COLLISIONS IN COLD DIPOLAR GASES." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/30.

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Inelastic collisions between dipolar molecules, assumed to be trapped in a static electric field at cold (> 10−3K) temperatures, are investigated and compared with elastic collisions. For molecules with a Λ-doublet energy-level structure, a dipole moment arises because of the existence of two nearly degenerate states of opposite parity, and the collision of two such dipoles can be solved entirely analytically in the energy range of interest. Cross sections and rate constants are found to satisfy simple, universal formulas. In contrast, for molecules in a Σ electronic ground state, the static electric field induces a dipole moment in one of three rotational sublevels. Collisions between two rotor dipoles are calculated numerically; the results scale simply with molecule mass, rotational constant, dipole moment, and field strength. It might be expected that any particles interacting only under the influence of the dipole-dipole interaction would show similar behavior; however, the most important and general result of this research is that at cold temperatures inelastic rate constants and cross sections for dipoles depend strongly upon the internal structure of the molecules. The most prominent difference between the Λ-doublet and rotor molecules is variation of the inelastic cross section with applied field strength. For Λ-doublet dipoles, cross sections decrease with increasing field strength. For rotor dipoles, cross sections increase proportionally with the square of field strength. Furthermore, the rate constants of the two types of molecules depend very differently on the angular orientations of the dipoles in the electric field.
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Books on the topic "Cold Molecule"

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Collaborative Computational Project on Molecular Quantum Dynamics and Daresbury Laboratory, eds. Interactions of cold atoms and molecules. Daresbury, Warrington [England]: Collaborative Computational Project on Molecular Quantum Dynamics, Daresbury Laboratory, 2002.

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Jan, Witkowski, and Cold Spring Harbor Laboratory, eds. Illuminating life: Selected papers from Cold Spring Harbor Laboratory, 1903-1969. Cold Spring Harbor, N.Y: Cold Spring Harbor Laboratory Press, 2000.

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Molecular genetics of Escherichia coli. New York, NY: Guilford Press, 1989.

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Ebata, Takayuki, and Masaaki Fujii, eds. Physical Chemistry of Cold Gas-Phase Functional Molecules and Clusters. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9371-6.

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Wu, Xing. A Centrifuge Decelerator and a Thermometer for Cold Polar Molecules. München: Universitätsbibliothek der TU München, 2017.

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The science of cold fusion phenomenon. Amsterdam: Elsevier, 2006.

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H, Chen Tony H., Uemura M, and Fujikawa S, eds. Cold hardiness in plants: Molecular genetics, cell biology, and physiology. Wallingford, Oxfordshire, UK: CABI Pub., 2005.

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Kozima, Hideo. The science of the cold fusion phenomenon. Oxford: Elsevier, 2006.

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The road to discovery: A short history of Cold Sprng Harbor Laboratory. Cold Spring Harbor, New York: Cold Spring Harbor Laboratory Press, 2016.

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1947-, Witkowski J. A., Gann Alexander, Sambrook Joseph, and Cold Spring Harbor Laboratory, eds. Life illuminated: Selected papers from Cold Spring Harbor : volume 2, 1972-1994. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press, 2008.

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Book chapters on the topic "Cold Molecule"

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Tiemann, Eberhard. "Cold Molecules." In Interactions in Ultracold Gases, 175–214. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603417.ch4.

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Koch, Christiane P. "Quantum Effects in Cold and Controlled Molecular Dynamics." In Molecular Beams in Physics and Chemistry, 477–90. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63963-1_21.

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AbstractThis chapter discusses three examples of quantum effects that can be observed in state-of-the-art experiments with molecular beams—scattering resonances as a probe of interparticle interactions in cold collisions, the protection of Fano-Feshbach resonances against decay despite resonant coupling to a scattering continuum, and a circular dichroism in photoelectron angular distributions arising in the photoionization of randomly oriented chiral molecules. The molecular beam setup provides molecules in well-defined quantum states. This, together with a theoretical description based on first principles, allows for excellent agreement between theoretical prediction and experimental observation and thus a rigorous understanding of the observed quantum effects.
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Dulieu, Olivier, Claude Amiot, Ricardo Gutterres, Françoise Masnou-Seeuws, N. Vanhaecke, C. Lisdat, D. Comparat, et al. "C. Cold Molecules." In Interactions in Ultracold Gases, 445–74. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603417.ch17.

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Peters, Nils, Martin Dichgans, Sankar Surendran, Josep M. Argilés, Francisco J. López-Soriano, Sílvia Busquets, Klaus Dittmann, et al. "COLD." In Encyclopedia of Molecular Mechanisms of Disease, 386. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-29676-8_7821.

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Germain, Aurèle, Marta Corno, and Piero Ugliengo. "Computing Binding Energies of Interstellar Molecules by Semiempirical Quantum Methods: Comparison Between DFT and GFN2 on Crystalline Ice." In Computational Science and Its Applications – ICCSA 2021, 632–45. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-86976-2_43.

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AbstractInterstellar Grains (IGs) spread in the Interstellar Medium (ISM) host a multitude of chemical reactions that could lead to the production of interstellar Complex Organic Molecules (iCOMs), relevant in the context of prebiotic chemistry. These IGs are composed of a silicate-based core covered by several layers of amorphous water ice, known as a grain mantle. Molecules from the ISM gas-phase can be adsorbed at the grain surfaces, diffuse and react to give iCOMs and ultimately desorbed back to the gas phase. Thus, the study of the Binding Energy (BE) of these molecules at the water ice grain surface is important to understand the molecular composition of the ISM and its evolution in time. In this paper, we propose to use a recently developed semiempirical quantum approach, named GFN-xTB, and more precisely the GFN2 method, to compute the BE of several molecular species at the crystalline water ice slab model. This method is very cheap in term of computing power and time and was already showed in a previous work to be very accurate with small water clusters. To support our proposition, we decided to use, as a benchmark, the recent work published by some of us in which a crystalline model of proton-ordered water ice (P-ice) was adopted to predict the BEs of 21 molecules relevant in the ISM. The relatively good results obtained confirm GFN2 as the method of choice to model adsorption processes occurring at the icy grains in the ISM. The only notable exception was for the CO molecule, in which both structure and BE are badly predicted by GFN2, a real pity due to the relevance of CO in astrochemistry.
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Sugiki, Toshihiko, Toshimichi Fujiwara, and Chojiro Kojima. "Cold-Shock Expression System in E. coli for Protein NMR Studies." In Methods in Molecular Biology, 345–57. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-6887-9_23.

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Hiilovaara-Teijo, M., and E. T. Palva. "Molecular responses in cold-adapted plants." In Cold-Adapted Organisms, 349–84. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-06285-2_20.

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Lee, Byeong-ha, YongSig Kim, and Jian-Kang Zhu. "Molecular Genetics of Plant Responses to Low Temperatures." In Plant Cold Hardiness, 3–16. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-0711-6_1.

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De Geus, E. J. "Search for Cold Molecular Gas." In New Extragalactic Perspectives in the New South Africa, 373–87. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0335-7_45.

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Pearce, Roger S., M. Alison Dunn, and Monica A. Hughes. "Molecular Biology of Cold Tolerance." In Interacting Stresses on Plants in a Changing Climate, 681–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-78533-7_44.

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Conference papers on the topic "Cold Molecule"

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DREWSEN, M. "COLD MOLECULAR IONS: SINGLE MOLECULE STUDIES." In Proceedings of the XXI International Conference on Atomic Physics. WORLD SCIENTIFIC, 2009. http://dx.doi.org/10.1142/9789814273008_0031.

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Ishkhanyan, A. "Demkov-Kunike model in cold molecule formation." In International Conference on Laser Physics 2010, edited by Aram V. Papoyan. SPIE, 2010. http://dx.doi.org/10.1117/12.890515.

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Jendoubi, I., H. Berriche, and H. Ben Ouada. "Theoretical study and formation prediction of the ultra-cold molecule RbLi." In INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2009: (ICCMSE 2009). AIP, 2012. http://dx.doi.org/10.1063/1.4771785.

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Eerkens, Jeff W., Jay F. Kunze, and Leonard J. Bond. "Laser Isotope Enrichment for Medical and Industrial Applications." In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89767.

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Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation repression. In this scheme, a gas of the selected isotopes for enrichment is irradiated with a laser at a particular wavelength that would excite only one of the isotopes. The entire gas is subjected to low temperatures sufficient to cause condensation on a cold surface or coagulation in the gas. Those molecules in the gas that the laser excited are not as likely to condense or dimerize (coagulate into a double molecule, called a dimer) as unexcited molecules. Hence in cold-wall condensation, gas drawn out of the system is enriched in the isotope that was laser-excited. We have evaluated the relative energy required in this process if applied on a commercial scale. We estimate the energy required for laser isotope enrichment is about 30% of that required in centrifuge separations, and 2% of that required by use of “calutrons”.
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Langi, Gladys Emmanuella Putri, Maelita R. Moeis, Ihsanawati, and Ernawati Arifin Giri-Rachman. "Molecular cloning and cold shock induced overexpression of the DNA encoding phor sensor domain from Mycobacterium tuberculosis as a target molecule for novel anti-tubercular drugs." In 4TH INTERNATIONAL CONFERENCE ON MATHEMATICS AND NATURAL SCIENCES (ICMNS 2012): Science for Health, Food and Sustainable Energy. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4868830.

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Tuncel, Jon, Bahram Valamehr, Xu Yuan, Francisco Martinez, Nicholas Brookhouser, Philip Chu, Duygu Ozmadenci, et al. "288 Targeting cold tumors using iPSC-derived CAR T cells directed to the immune checkpoint molecule and tumor-associated antigen B7-H3." In SITC 37th Annual Meeting (SITC 2022) Abstracts. BMJ Publishing Group Ltd, 2022. http://dx.doi.org/10.1136/jitc-2022-sitc2022.0288.

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Baer, Tomas. "Time Resolved Studies in the Gas Phase: Reaction Dynamics and Threshold Photoelectron Spectroscopy." In Free-Electron Laser Applications in the Ultraviolet. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/fel.1988.fb2.

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The high intensity, resolution, and brightness of the free electron laser (FEL) radiation is now making possible pump-probe experiments of excited state lifetimes in the picosecond domain in energy ranges not previously attainable by standard lasers. In addition, the short pulses will make possible electron TOF studies for measuring threshold photoelectron spectra with resolutions to 1 cm-1. The major requirement for pump-probe experiment is that the sum of the two laser energies be greater than the ionization potential of the molecule being investigated. The FEL can be used either as a pump to investigate high energy states, or as a probe for low energy states excited by infra-red or visible lasers. TPES of cold molecules will provide new information about vibrational modes in ions and structural information from the analysis of the rotational structure.
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Zhu, Taishan, Wenjing Ye, and Jun Zhang. "Size Dependent Orientation of Knudsen Force." In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75237.

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Knudsen force acting on a heated microbeam adjacent to a cold substrate in a rarefied gas is a mechanical force created by unbalanced thermal gradients. The measured force has its direction pointing towards the side with a lower thermal gradient and its magnitude vanishes in both continuum and free-molecule limits. In our previous study, negative Knudsen forces were discovered at the high Knudsen regime before diminishing in the free-molecule limit. Such a phenomenon was however not observed in the experiment. In this paper, the existence of such a negative Knudsen force is further confirmed using both numerical simulation and theoretical analysis. The asymptotic order of the Knudsen force near the collisionless limit is analyzed and the analytical expression of its leading term is provided, from which approaches for the enhancement of negative Knudsen forces are proposed.
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deCarvalho, Robert, Jonathan Weinstein, Bretislav Friedrich, and John Doyle. "Trapping cold molecules." In High-Power Lasers and Applications, edited by Charles W. Wilkerson, Jr. SPIE, 2002. http://dx.doi.org/10.1117/12.463837.

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Lewandowski, Heather J., L. Paul Parazzoli, and Daniel Lobser. "Cold Free-Radical NH Molecules." In Laser Science. Washington, D.C.: OSA, 2006. http://dx.doi.org/10.1364/ls.2006.ltuh1.

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Reports on the topic "Cold Molecule"

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Ramirez-Serrano, Jamie, David W. Chandler, Kevin Strecker, and Larry A. Rahn. Ultra-cold molecule production. Office of Scientific and Technical Information (OSTI), December 2005. http://dx.doi.org/10.2172/875983.

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Strecker, Kevin E., and David W. Chandler. Micro-Kelvin cold molecules. Office of Scientific and Technical Information (OSTI), October 2009. http://dx.doi.org/10.2172/986607.

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Wessel, J. E. Ion dip spectroscopy of cold molecules and ions. Progress report. Office of Scientific and Technical Information (OSTI), August 1988. http://dx.doi.org/10.2172/674623.

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Wu, Congjun. Unconventional States of Matter with Cold Atoms and Dipolar Molecules. Fort Belvoir, VA: Defense Technical Information Center, August 2014. http://dx.doi.org/10.21236/ada609971.

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Lewandowski, Heather. Resonant Energy Transfer in a System of Cold Trapped Molecules. Fort Belvoir, VA: Defense Technical Information Center, October 2011. http://dx.doi.org/10.21236/ada565577.

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Wessel, J. Ion dip spectroscopy of cold molecules and ions. Progress report and renewal proposal. Office of Scientific and Technical Information (OSTI), August 1987. http://dx.doi.org/10.2172/674624.

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Cowley, S. C., and R. M. Kulsrud. Some considerations of cold fusion including the calculation of fusion rates in molecules of hydrogen isotopes. Office of Scientific and Technical Information (OSTI), November 1989. http://dx.doi.org/10.2172/5589183.

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Moore, Gloria A., Gozal Ben-Hayyim, Charles L. Guy, and Doron Holland. Mapping Quantitative Trait Loci in the Woody Perennial Plant Genus Citrus. United States Department of Agriculture, May 1995. http://dx.doi.org/10.32747/1995.7570565.bard.

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As is true for all crops, production of Citrus fruit is limited by traits whose characteristics are the products of many genes (i.e. cold hardiness). In order to modify these traits by marker aided selection or molecular genetic techniques, it is first necessary to map the relevant genes. Mapping of quantitative trait loci (QTLs) in perennial plants has been extremely difficult, requiring large numbers of mature plants. Production of suitable mapping populations has been inhibited by aspects of reproductive biology (e.g. incompatibility, apomixis) and delayed by juvenility. New approaches promise to overcome some of these obstacles. The overall objective of this project was to determine whether QTLs for environmental stress tolerance could be effectively mapped in the perennial crop Citrus, using an extensive linkage map consisting of various types of molecular markers. Specific objectives were to: 1) Produce a highly saturated genetic linkage map of Citrus by continuing to place molecular markers of several types on the map. 2) Exploiting recently developed technology and already characterized parental types, determine whether QTLs governing cold acclimation can be mapped using very young seedling populations. 3) Determine whether the same strategy can be transferred to a different situation by mapping QTLs influencing Na+ and C1- exclusion (likely components of salinity tolerance) in the already characterized cross and in new alternative crosses. 4) Construct a YAC library of the citrus genome for future mapping and cloning.
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Davidson, Irit, Hsing-Jien Kung, and Richard L. Witter. Molecular Interactions between Herpes and Retroviruses in Dually Infected Chickens and Turkeys. United States Department of Agriculture, January 2002. http://dx.doi.org/10.32747/2002.7575275.bard.

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Tumors in commercial poultry are caused mainly by infection with avian herpes and retroviruses, the herpesvirus Marek's disease virus (MDV) and the retroviruses, reticuloendotheliosis (REV), lymphoid leukosis, subgroups A-I and J (ALV and ALV-J) in chickens, or Iymphoprolipherative disease (LPDV) in turkeys. Infection with one virus aggravates the clinical outcome of birds that are already infected by another oncogenic virus. As these viruses do not interfere for infection, MDV and one or more retroviruses can infect the same flock, the same bird and the same cell. While infecting the same cell, herpes and retroviruses might interact in at least three ways: a) Integration of retrovirus genomes, or genomic fragments (mainly the LTR) into MDV;b) alteration of LTR-driven expression of retroviral genes by MDV immediate- early genes, and c) by herpesvirus induced cellular transcriptional factors. The first type of molecular interaction have been demonstrated to happen efficiently in vitro by Dr. Kung, in cases multiple infection of cell cultures with MDV and REV or MDV and ALV. Moreover, Dr. Witter showed that an in vitro-created recombinant, RM1, had altered in vitro replication and in vivo biological properties. A more comprehensive characterization of RM1 was carried out in the present project. We sought to highlight whether events of such integrations occur also in the bird, in vivo. For that, we had first to determine the prevalence of dually-infected individual birds in commercial flocks, as no systematic survey has been yet reported. Surprisingly, about 25% of the commercial flocks infected with avian oncogenic viruses had a multiple virus infection and 5% of the total samples ana lysed had multiple virus sequences. Then, we aimed to evaluate and characterize biologically and molecularly the resulting recombinants, if formed, and to analyse the factors that affect these events (virus strains, type and age of birds and time interval between the infection with both viruses). The perception of retrovirus insertions into herpesviruses in vivo is not banal, as the in vivo and in vitro systems differ in the viral-target cells, lymphocytes or fibroblasts, in the MDV-replicative type, transforming or productive, and the immune system presence. We realized that previous methods employed to study in vitro created recombinant viruses were not adequate for the study of samples taken directly from the bird. Therefore, the Hot Spot-combined PCR was developed based on the molecularly known RM1 virus. Also, the PFGE that was used for tissue cultured-MDV separation was inefficient for separating MDV from organs, but useful with feather tips as a source of bird original MDV. Much attention was dedicated now to feathers, because if a recombinant virus would be formed in vivo, its biological significance would be evident by horizontal dissemination through the feathers. Major findings were: a) not only in vitro, but also in vivo MDV and retrovirus co-infections lead to LTR integrations into MDV. That was shown by the detection of chimeric molecules. These appeared in low quantities and as quasispecies, thus interfering with sequence analysis of cloned gel-purified chimeric molecules. Mainly inserts were located in the repeat long MDV fragments. In field birds chimeric molecules were detected at a lower frequency (2.5%) than in experimentally infected birds (30-50%). These could be transmitted experimentally to another birds by inoculation with chimeric molecules containing blood. Several types of chimeric molecules were formed, and same types were detected in birds infected by a second round. To reproduce viral integrations, in vivo infection trials were done with field inoculate that contained both viruses, but the chimeric molecule yield was undetectable.
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Banai, Menachem, and Gary Splitter. Molecular Characterization and Function of Brucella Immunodominant Proteins. United States Department of Agriculture, July 1993. http://dx.doi.org/10.32747/1993.7568100.bard.

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The BARD project was a continuation of a previous BARD funded research project. It was aimed at characterization of the 12kDa immunodominant protein and subsequently the cloning and expression of the gene in E. coli. Additional immunodominant proteins were sought among genomic B. abortus expression library clones using T-lymphocyte proliferation assay as a screening method. The 12kDa protein was identified as the L7/L12 ribosomal protein demonstrating in the first time the role a structural protein may play in the development of the host's immunity against the organism. The gene was cloned from B. abortus (USA) and B. melitensis (Israel) showing identity of the oligonucleotide sequence between the two species. Further subcloning allowed expression of the protein in E. coli. While the native protein was shown to have DTH antigenicity its recombinant analog lacked this activity. In contrast the two proteins elicited lymphocyte proliferation in experimental murine brucellosis. CD4+ cells of the Th1 subset predominantly responded to this protein demonstrating the development of protective immunity (g-IFN, and IL-2) in the host. Similar results were obtained with bovine Brucella primed lymphocytes. UvrA, GroE1 and GroEs were additional Brucella immunodominant proteins that demonstrated MHC class II antigenicity. The role cytotoxic cells are playing in the clearance of brucella cells was shown using knock out mice defective either in their CD4+ or CD8+ cells. CD4+ defective mice were able to clear brucella as fast as did normal mice. In contrast mice which were defective in their CD8+ cells could not clear the organisms effectively proving the importance of this subtype cell line in development of protective immunity. The understanding of the host's immune response and the expansion of the panel of Brucella immunodominant proteins opened new avenues in vaccine design. It is now feasible to selectively use immunodominant proteins either as subunit vaccine to fortify immunity of older animals or as diagnostic reagents for the serological survaillance.
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