Готові списки джерел за темами / Molecules and Processes

Добірка наукової літератури з теми "Molecules and Processes"

Автор: Grafiati
Опубліковано: 7 вересня 2023

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Статті в журналах з теми "Molecules and Processes"

1

ZACHARIAS, H. "LASER SPECTROSCOPY OF DYNAMICAL SURFACE PROCESSES." International Journal of Modern Physics B 04, no. 01 (January 1990): 45–91. http://dx.doi.org/10.1142/s0217979290000036.

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Physical phenomena associated with energy deposition into adsorbed molecules will be discussed. This energy may be provided to the adsorbate either thermally, by a catalytic surface reaction or by laser radiation. When enough energy is supplied adsorbed molecules eventually desorb from the substrate. Observation of the desorption flux with internal state selection provides detailed information about the molecular dynamics in this process, because the internal excitations are associated with the dynamics on the potential energy hypersurface. The rotational cooling effect previously observed in molecular beam scattering has also been found for desorption. In several systems strong vibrational excitation has been observed. Recent developments permit in addition the velocity distributions of molecules to be determined with internal quantum state resolution. The complete energetics of desorbing molecules can thus be determined. Finally, making use of the polarized nature of the laser radiation, alignment effects in the desorption can be observed, permitting to analyze the vector properties of the rotational angular momentum.
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2

Robson, Alex, Kevin Burrage, and Mark C. Leake. "Inferring diffusion in single live cells at the single-molecule level." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1611 (February 5, 2013): 20120029. http://dx.doi.org/10.1098/rstb.2012.0029.

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The movement of molecules inside living cells is a fundamental feature of biological processes. The ability to both observe and analyse the details of molecular diffusion in vivo at the single-molecule and single-cell level can add significant insight into understanding molecular architectures of diffusing molecules and the nanoscale environment in which the molecules diffuse. The tool of choice for monitoring dynamic molecular localization in live cells is fluorescence microscopy, especially so combining total internal reflection fluorescence with the use of fluorescent protein (FP) reporters in offering exceptional imaging contrast for dynamic processes in the cell membrane under relatively physiological conditions compared with competing single-molecule techniques. There exist several different complex modes of diffusion, and discriminating these from each other is challenging at the molecular level owing to underlying stochastic behaviour. Analysis is traditionally performed using mean square displacements of tracked particles; however, this generally requires more data points than is typical for single FP tracks owing to photophysical instability. Presented here is a novel approach allowing robust Bayesian ranking of diffusion processes to discriminate multiple complex modes probabilistically. It is a computational approach that biologists can use to understand single-molecule features in live cells.
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3

Bogdan, Diana, and Valer Tosa. "Processes in Isotopes and Molecules." Journal of Physics: Conference Series 182 (July 1, 2009): 011001. http://dx.doi.org/10.1088/1742-6596/182/1/011001.

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4

van Dishoeck, Ewine F. "Photodissociation Processes of Astrophysical Molecules." Symposium - International Astronomical Union 120 (1987): 51–65. http://dx.doi.org/10.1017/s0074180900153793.

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5

Letokhov, V. S. "Infrared multiphoton processes in molecules." Applied Physics B Photophysics and Laser Chemistry 47, no. 3 (November 1988): 207. http://dx.doi.org/10.1007/bf00697338.

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6

Jiang, Chen-Wei, Xiang Zhou, Rui-Hua Xie, and Fu-Li Li. "Semiclassical Molecular Dynamics Simulations for Ultrafast Processes in Molecules." Quantum Matter 2, no. 5 (October 1, 2013): 353–63. http://dx.doi.org/10.1166/qm.2013.1067.

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7

Hashemi, Reza, Alexander Kühn, and Eugen Illenberger. "Electron capture induced processes in molecules and molecular aggregates." International Journal of Mass Spectrometry and Ion Processes 100 (October 1990): 753–84. http://dx.doi.org/10.1016/0168-1176(90)85107-d.

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Byassee, Tyler A., Warren C. W. Chan, and Shuming Nie. "Probing Single Molecules in Single Living Cells." Microscopy and Microanalysis 7, S2 (August 2001): 28–29. http://dx.doi.org/10.1017/s1431927600026210.

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Direct observation of single molecules and single molecular events inside living cells could dramatically improve our understanding of basic cellular processes (e.g., signal transduction and gene transcription) as well as improving our knowledge on the intracellular transport and fate of therapeutic agents (e.g., antisense RNA and gene therapy vectors). However, a key remaining question is whether single-molecule methodologies could be developed to study complex molecular processes in living cells. in contrast to clean and well-controlled conditions in-vitro, the intracellular environment contains a broad collection of biological macromolecules and fluorescent materials such as porphyrins and flavins. This complex environment is known to produce intense background fluorescence, commonly known as autofluorescence. Thus, a major concern is that this intracellular background could overwhelm the relatively weak signals arising from single molecules.We demonstrate that fluorescence detection of single molecules can be achieved by tightly focusing a laser beam into a living cell (see Figure 1). The observed background fluorescence is indeed higher than that in-vitro (e.g., pure biological buffer), but this background is continuous and stable, and does not significantly interfere with the measurement of single-molecule photon bursts. Specifically, we report single-molecule results on three types of extrinsic fluorescent molecules in cultured human HeLa cells (a cervical cancer cell line).
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Басалаев, А. А., А. Г. Бузыкин, В. В. Кузьмичев, М. Н. Панов, А. В. Петров та О. В. Смирнов. "Взаимодействие alpha-частиц keV-энергий с молекулами глицил-лейцина". Письма в журнал технической физики 47, № 12 (2021): 23. http://dx.doi.org/10.21883/pjtf.2021.12.51062.18746.

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Radiation damage to isolated glycyl-leucine (C8H16N2O3) molecules caused by interaction with He2+ ions was studied. For the first time, the relative cross sections of the main processes of changes in the charge state of the collision partners and the relative cross sections of the fragmentation processes of singly and doubly charged molecular ions formed during single collisions of glycyl-leucine molecules with ions have been obtained. The optimized geometry of the molecule and singly charged glycyl-leucine ion was calculated using the density functional theory (DFT).
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10

Liu, Pingan, Junpeng Liu, and Mengjun Wang. "Adsorption of ethanol molecules on the Al (1 1 1) surface: a molecular dynamic study." Royal Society Open Science 6, no. 1 (January 2019): 181189. http://dx.doi.org/10.1098/rsos.181189.

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The adsorption process of ethanol molecules on Al slabs was investigated by molecular dynamic simulations with a ReaxFF force field. The force field used in this paper has been validated by comparing adsorption energy results with quantum mechanical (QM) calculations. All simulations were performed under the canonical (NVT) ensemble. The single-molecule adsorption simulation shows that the hydroxyl group plays a more important role in the whole progress than the ethyl group. Besides, decomposition of hydroxyl groups was also observed during multimolecule adsorption processes. Simulations of adsorption processes of Al slab by ethanol molecules at different temperatures and pressures (controlled by the number of ethanol molecules) was also performed. System energy and radial distribution function (RDF) plots were invoked to describe adsorption processes and centro-symmetry parameter (CSP) analysis was adopted to study the surface properties with coating layers. Our results indicate that the whole adsorption process can be divided into two periods and the greater the pressure, the more ethanol molecules diffuse into the Al slab. How raising the temperature helps the adsorption processes is related to the initial number of molecules. The crystal structure of the Al surface will become amorphous under the constant impact of ethanol molecules.
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Більше джерел

Дисертації з теми "Molecules and Processes"

1

Vichetti, Rafael Mário [UNESP]. "Síntese dos isótopos do monóxido de carbono no meio interestelar." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/91889.

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Made available in DSpace on 2014-06-11T19:25:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-21Bitstream added on 2014-06-13T19:53:20Z : No. of bitstreams: 1 vichietti_rm_me_rcla.pdf: 842604 bytes, checksum: 731ca276a75c1b92840e57bd7497b5e1 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
De acordo com os resultados observacionais de condensações de nuvens moleculares escuras, grandes variações na razão 13CO/C18O são observadas quando se comparam os resultados obtidos nas condensações situadas dentro da mesma nuvem, bem como de nuvem para nuvem. O valor médio dessa razão na condensação principal de Ophiuchus é inferior a 5. Por outro lado, o valor encontrado nas condensações que estão situadas ao norte de Oph é maior que 10. Grandes diferenças também são encontradas quando se comparam os resultados observacionais de diferentes nuvens escuras, tais como Ophiuchus e Taurus, onde são observados também um decréscimo da razão C18O/C17O com o aumento da densidade. Os processos químicos e físicos que governam essas variações ainda não estão claros. Nesse sentido, o objetivo da presente proposta é analisar a influência do colapso gravitacional de condensações de nuvens moleculares escuras na síntese das moléculas CO, C17O, C18O, 13CO, 13C17O e 13C18O. Tal análise é feita com base em comparações entre modelos que consideram diferentes condições entre si, tais como, tamanho da cadeia química, velocidade de colapso, densidade inicial e processos de congelamento de espécies químicas na superfície de grãos de poeira. Os resultados obtidos mostram que o tamanho da cadeia química tem influência nas razões 13CO/C18O e C18O/C17O, mas não tanto quanto a densidade inicial e a velocidade do colapso. Além disso, o congelamento das espécies químicas nos grãos é mais significativo nos estágios mais avançados da evolução da condensação. Os modelos de condensações escuras que sofrem colapso gravitacional lento e em queda livre reproduzem satisfatoriamente as razões 13CO/C18O e C18O/C17O observadas, o que permite concluir que o colapso gravitacional pode ter um importante efeito nas referidas razões.
According to the observational results of dark molecular clouds condensations, large variations in the ratio 13CO/C18O are observed when comparing the results obtained in the condensations located within the same cloud and cloud to cloud. The average value of this ratio in the main condensation of Ophiuchus is below 5. On the other hand, the value found in the condensations that are located north of Oph is larger than 10. Large differences are also found when comparing the observational results of different dark clouds such as Ophiuchus and Taurus, in which are also found a decrease of the C18O/C17O ratio with increasing density. The chemical and physical processes that govern these variations are still unclear. In this sense, the objective of this proposal is to analyze the influence of the gravitational collapse of centrally condensed clumps of dense molecular gas in the synthesis of the CO, C17O, C18O, 13CO, 13C17O and 13C18O molecules. This analysis is based on comparisons among models that consider different condition, such as, chemical chain, initial density, speed of collapse and freezing processes of the chemical species on the surface of dust grains. The results show that the size of the chemical chain has influence on the 13CO/C18O and C18O/C17O ratios, but they are not as important as the initial density and the speed of the collapse. Furthermore, the freezing of chemical species on the grains occurs at later times of the collapse. The models of a gravitational free-fall collapsing core and of slowly contracting core with higher initial density are consistent with observations. These results indicate that the gravitational collapse of molecular cores can have an important effect in the 13CO/C18O and C18O/C17O ratios.
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2

Bryan, William Alexander. "Ultrafast processes in small molecules." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248347.

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3

Chen, Tao. "Ions colliding with molecules and molecular clusters : fragmentation and growth processes." Doctoral thesis, Stockholms universitet, Fysikum, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-117114.

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In this work we will discuss fragmentation and molecular growth processes in collisions of Polycyclic Aromatic Hydrocarbon (PAH) molecules, fullerenes, or their clusters with atoms or atomic ions. Simple collision models as well as molecular structure calculations are used to aid the interpretations of the present and other experimental results. Fragmentation features at center-of-mass collision energies around 10 keV are dominated by interactions between the fast ion/atom and the electron cloud in the molecules/clusters (electronic stopping processes). This electronic excitation energy is rapidly distributed on the vibrational degrees of freedom of the molecule or of the molecules in a cluster and may result in fragmentation. Here, the fragmentation is statistical and favors the lowest-energy dissociation channels which are losses of intact molecules from clusters, H- and C2H2-losses from isolated PAHs, and C2-loss from fullerene monomers. We will also discuss the possibility of formation of molecular H2 direct from native PAHs which reach high enough energies when interacting with ions, electrons, or photons. For the experiments at lower center of mass collision energies (~100 eV) a single atom may be knocked out in close atom-atom interaction. Such non-statistical fragmentation are due to nuclear stopping processes and gives highly reactive fragments which may form covalent bonds with other molecules in a cluster on very short time scales (picoseconds). This process may be important when considering the formation of new species. For collision between 12 keV Ar2+ and clusters of pyrene (C16H10) molecules, new molecules, e.g. C17H10+, C30H18+, C31H19+, etc are detected. We also observe molecular fusion processes for He and Ar ions colliding with clusters of C60 molecules. These and related molecular fusion processes may play a key role for understanding molecular growth processes under certain astrophysical conditions.
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4

Vidonne, Annick. "Integrating replication processes with mechanically interlocked molecules." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/913.

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5

Toliautas, Stepas. "Electronic excitation processes of photoactive organic molecules." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140929_100526-37294.

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Evolution of the electronic excitation is a general process that can be used to explain many natural and artificial phenomena, such as photosynthesis in plants and bacteria, biological mechanism of vision, and operating principles of optomechanical and optoelectronic devices. This process is theoretically modeled by solving the time-dependent Schroedinger equation. However, such treatment is too computationally expensive to be used for practical molecular systems. Therefore, either models of the structure of the systems or the solving procedure itself must be simplified to get the desired results. The main goal of the research presented in this dissertation was to study processes caused by the electronic excitation in photoactive molecules using computational methods of electronic structure (i. e. solving the simpler time-independent Schroedinger equation) and to construct the potential energy surface models describing the energy relaxation in the investigated molecules. It is shown that the results of different investigations performed using the same procedure provide explanations of different phenomena in various compounds, such as: proton transfer in polar solvent, performed by a functional group of the bacteriorhodopsin protein; optomechanical cycle of the indolo-benzoxazine compound; efficient phosphorescence of the silicon-based organic polymer; and optical properties of organometallic emitter compound with additional charge-carrier groups.
Elektroninio sužadinimo evoliucija šviesai jautriose molekulėse yra reiškinys, kuriuo remiantis įmanoma nagrinėti daugelį natūralių ir dirbtinių procesų: augalų ir bakterijų fotosintezę, regos mechanizmą, optomechaninių bei optoelektroninių prietaisų (pavyzdžiui, organinių šviestukų) veikimą. Teoriškai šis reiškinys modeliuojamas sprendžiant laikinę Šriodingerio lygtį. Deja, toks sprendimas realiems, praktiškai panaudojamiems junginiams šiandien yra per sudėtingas uždavinys, todėl jį tenka keisti supaprastinant nagrinėjamų junginių modelius arba sprendimo metodiką. Šioje disertacijoje aprašomų tyrimų tikslas buvo elektroninės struktūros skaičiavimų metodais (t. y. sprendžiant paprastesnę nuostoviąją Šriodingerio lygtį) ištirti elektroninio sužadinimo sukeltus procesus fotoaktyviose molekulėse ir sudaryti sužadinimo relaksaciją apibūdinančius potencinės energijos paviršių modelius. Parodoma, jog ta pačia metodika atliekamų tyrimų rezultatai paaiškina įvairiuose junginiuose vykstančius reiškinius: bakteriorodopsino baltymo funkcinės grupės vykdomą protono pernašą poliniame tirpiklyje, indolo-benzoksazino junginio optomechaninį ciklą, našią fosforescenciją organiniame silicio polimere bei šviestukams naudojamo metaloorganinio komplekso su prijungtomis krūvininkų pernašos grupėmis ypatybes.
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6

Howle, Christopher Roy. "Decay processes of photoexcited molecules in the VUV : comparison with ion/molecule reactions." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421712.

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7

Suárez, Rojas Noslen. "Strong-field processes in atoms and polyatomic molecules." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/461458.

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In this thesis, we develop a general theory to describe the dynamics of electrons that are ionized when an atom or molecule is exposed to a strong low frequency laser field. Our approach extends and improves the well-established theoretical strong-field approximation (SFA). Additionally, our modified strong field approximation (MSFA) can be extended in a natural way from atomic systems to a more complex molecules and multielectron systems. Our scheme involves two innovative aspects: (i) First, the bound-continuum and rescattering matrix elements can be analytically computed for both atomic and multicenter molecular systems, using a nonlocal short range (SR), but separable, potential. When compared with the standard models, these analytical derivations make possible to directly examine how the ATI and HHG spectra depend on the driven media and laser-pulse features. Furthermore, our model allows us to disentangle the different processes contributing to the total spectra, amongst other capabilities, and it allows us to adjust both the internuclear separation and atomic or molecular potential in a direct and simple way. Furthermore, we can turn on and off contributions having distinct physical origins or corresponding to different mechanisms that correspond to (1) direct tunneling ionization; (2) electron escattering/recombining on the center of origin; and, finally, (3) electron rescattering/recombining on a different center. (ii) Second, the multicenter matrix elements in our theory are free from nonphysical coordinate-systemdependent terms; this is accomplished by adapting the coordinate system to the center from which the corresponding time-dependent wave function originates. Having established the basic formalism, we then study the HHG and ATI processes for a variety of atomic and molecular systems. We compare the SFA results with the full numerical solutions of the timedependent Schrödinger equation (TDSE), when available, within the few-cycle pulse regime. We show how our MSFA can be used to look inside the underlying physics of those phenomena. With our tool it is possible to investigate the interference features, ubiquitously present in every strong-field phenomenon involving a multicenter target, or to describe laser-induced electron diffraction (LIED) measurements retrieving molecular structural information from the photoelectron spectra. Our approach paves the way to study the HHG and ATI processes in much more complex molecular targets. Additionally, it potentially can be extended to study these kind of recombination and rescattering scenarios in solid targets.
En esta tesis, desarrollamos una teoría general para describir la dinámica de ionización de electrones cuando un átomo o molécula está expuesto a un campo externo fuerte y de longitud de onda larga. Nuestra teoría: la aproximación de campo fuerte modificada (MSFA), es capaz de describir la interacción de un pulso de luz, no sólo con átomos sino también con moléculas y sólidos. La MSFA está construida como una extensión natural y consecuente del modelo atómico, describiendo desde los sistemas más simples hasta las moléculas más complejas, incluyendo sistemas de muchos electrones. Nuestro enfoque abarca dos aspectos innovadores: (i) En primer lugar, los elementos de matriz que describen la dispersión e interacciones de electrones en el continuo se calculan analíticamente, tanto para sistemas atómicos como moleculares. Esto se logra utilizando un tipo de potencial de corto alcance (SR), no local y separable. En comparación con los modelos estándares, estas derivaciones analíticas permiten examinar directamente cómo los espectros ATI y HHG dependen de las características del pulso láser. Nuestra derivación analítica permite diferenciar los diferentes procesos que contribuyen al espectro total, además de que nos permite fijar la distancia internuclear y el potencial atómico o molecular de una manera directa y sencilla. También es posible activar y desactivar las contribuciones que tienen diferentes orígenes físicos o que corresponden a diferentes mecanismos como, (1) ionización directa por túnel; (2) dispersión/recombinación de electrones en el átomo de ionización; y, por último, (3) dispersión/recombinación de electrones en un átomo distinto al de ionización. (ii) En segundo lugar, en nuestra teoría los elementos matriciales de los sistemas multi-atómicos se encuentran libres de calibraciones no físicas y son independientes del sistema de coordenadas. Esto se consigue adaptando el sistema de coordenadas al átomo del que se origina la correspondiente función de onda dependiente del tiempo. Una vez establecido el formalismo básico del MSFA, estudiamos los procesos de HHG y ATI para una gran variedad de sistemas atómicos y moleculares. Comparamos los resultados del MSFA con las soluciones numéricas de la ecuación de Schrödinger dependiente del tiempo (TDSE), cuando sea posible. Demostramos que nuestro modelo de MSFA puede ser utilizado para estudiar la física de los procesos fundamentales que están detrás de HHG y ATI. Con esta herramienta es posible investigar los procesos de interferencia, inherentes a todos los fenómenos de campo fuerte, en sistemas multi-céntricos. También es posible describir mediciones experimentales de difracción de electrones inducida por láser (LIED), permitiendo recuperar información estructural mediante el análisis de los espectros de fotoelectrones. Nuestro modelo abre el camino para estudiar los procesos de HHG y ATI en sistemas de moléculas complejas. Además tiene la potencialidad de poder ser fácilmente extendido para estudiar procesos de recombinación y dispersión, no sólo en moléculas grandes, sino también en sólidos.
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8

Andrews, S. R. "Studies of double ionization and related electronic processes in molecules." Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635784.

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The major objective of these investigations was to develop a high-resolution double-charge-transfer spectrometer in order to measure vertical double-ionization energies of molecules, and to develop a thoeretical method to predict these energies economically. An overview of experimental techniques that have been used for the measurement of double-ionization energies is given in chapter 1; their advantages and restrictions are discussed and a brief review of double-charge-transfer spectroscopy studies to date is made. The various theoretical methods that are available for the studies of these processes are discussed in chapter 2, and a semi-empirical method based on the MSXα method is developed and tested for its effectiveness in predicting the complex singlet- and triplet-state energy distributions that exist in molecular dications; NH_3 and NO_2 were chosen for this purpose. Chapter 3 then describes in more detail the double-charge-transfer experiment, the spectrometers used in the studies presented in this thesis, and the modifications to that equipment. The next three chapters are devoted to the studies of double ionization of a wide variety of molecular dications. In chapter 4, theoretical predictions and interpretations of previous experimental results are presented; double-ionization energies of water, chloromethanes, iodomethanes and three metal hexacarbonyls (Cr, Mo, W) are predicted. This is followed in chapter 5 by joint theoretical and experimental studies initially of the triplet-state energies of ethane, allene and 1,1-dimethyl allene with the MS9 spectrometer, and then of ethyne, propyne and various alkyl-substituted amines with the high-resolution Finnigan 8230 spectrometer. The results are interpreted using the above semi-empirical theoretical technique. Finally, the possibility of studying singlet-state energies at high resolution is investigated in chapter 6, with joint experimental measurements and theoretical predictions of singlet-state energies of ethene, ethyne, propyne and allene being presented.
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9

Al-Edhari, Ali Jaber. "Complex organic molecules in solar-type star forming regions." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY048/document.

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Le but de la présente thèse est l'étude de la compléxité moléculaire dans les régions de formation stellaires. Cette thèse s'axe sur deux classes de molécule aux caractéristiques prébiotiques : les molécules organiques complexes et les cyanopolyynes.Dans ce contexte, j'ai analysé des données d'un seul échantillon de relevés spec- traux en exploitant des codes de transfert radiatif à l'équilibre thermodynamique local (LTE) et/ou non-LTE pour deux sources : une proto-étoile de type solaire dans un environnement calme (IRAS 16293-2422) et un proto-ama constitué de proto-étoile de type solaire (OMC2-FIR4).L'objectif est de trouver des similar- ités et des différences entre ces deux cas.J'ai utilisé des données issu de deux relevés spectraux : TIMASSS (The IRAS16293-2422 Millimeter And Submilimeter Spectral Survey) réalisés en 2011 (Caux et al. 2011), et ASAI(Astrochemical Surveys At IRAM) réalisés pen- dant la période 2013-2015 (eg Lopez-Sepulcre et al.2015). J'ai extrais les lignes (identification et intensité intégrée) en utilisant le paquet disponible publique- ment : CASSIS (Centre d'Analyse Scientifique de Spectres Infrarouges et Sub- millimetrique). Pour finir, j'ai utilisé le paquet GRAPES (GRenoble Analysis of Protostellar Envelope Spectral) afin de modéliser la distribution spectrale énergétique de ligne (SLED) des molécules détectées, mais aussi afin d'estimer leurs abondances à travers l'envelope de IRAS16293 et du coeur chaud OMC2- FIR4.Les principaux résultats de la thèse sont :1. Le premier recensement complet des molecules organiques complexes (COMs) dans IRAS162932. La première détéction de COMs dans l'enveloppe froide d'une proto-étoile de type solaire (IRAS16293-2422) supportant l'idée qu'un méchanisme de formation, relativement efficace pour les COMs détectées, doit exister en phase gazeuse froide.3. La découverte d'une fine corrélation entre le diméthyle-éther (DME) et le méthyle-formate (MF) suggère une relation mère fille entre ces deux espèces.4. La detection de formamide, espèce avec un très fort potentiel prébiotique, dans plusieurs protoétoiles incluant IRAS16293-2422 et OMC2-FIR4.5. Le recensement complet des cyanopolyynes dans IRAS16293 et OMC2- FIR4 avec la détection de HC3N, HC5N, DC3N et pour OMC2-FIR4: le C13 isotopologue du HC3N cyanopolyynes.Ces résultats sont le sujet principal de deux publications (Jaber et al.2014, ApJ; Lopez-Sepulcre, Jaber et al.2015,MNRAS), un article accepté (Jaber et al., A & A) et un article à soumettre (Jaber et al. A & A)
The present PhD thesis goal is the study of the molecular complexity in solar type star forming regions. It specifically focuses on two classes of molecules with a pre-biotic value, the complex organic molecules and the cyanopolyynes.At this scope, I analyzed data from single-dish spectral surveys by means of non-LTE or/and non-LTE radiative transfer codes in two sources, a solar type protostar in an isolated and quiet environment (IRAS16293-2422) and a proto-cluster of solar type protostars (OMC2-FIR4). The goal is to find similarities and differences between these two cases.I used data from two spectra surveys: TIMASSS (The IRAS16293-2422 Millimeter And Submillimeter Spectral Survey), which has been carried out in 2011 (Caux et al. 2011), and ASAI (Astrochemical Surveys At IRAM), which has been carried out in 2013-2015 (e.g. Lopez-Sepulcre et al. 2015).I extracted the lines (identification and integrated intensity) by means of the publicly available package CASSIS (Centre dAnalyse Scientifique de Spectres Infrarouges et Submillimtriques).Finally, I used the package GRAPES (GRenoble Analysis of Protostellar Envelope Spectra) to model the Spectral Line Energy Distribution (SLED) of the detected molecules, and to estimate their abundance across the envelope and hot corino of IRAS16293-2422 and OMC2-FIR4, respectively.The major results of the thesis are:1) The first full census of complex organic molecules (COMs) in IRAS16293-2422;2) The first detection of COMs in the cold envelope of a solar type protostar (IRAS16293-2422), supporting the idea that a relatively efficient formation mechanism for the detected COMs must exist in the cold gas phase;3) The discovery of a tight correlation between the dimethyl ether (DME) and methyl format (MF), suggesting a mother-daughter relationship;4) The detection of formamide, a species with a very high pre-biotic value, in several protostars, included IRAS16293-2422 and OMC2-FIR4;5) The full census of the cyanopolyynes in IRAS16293-2422 and OMC2-FIR4, with the detection of HC3N and HC5N, DC3N and, for OMC2-FIR4, the 13C isotopologue of HC3N cyanopolyynes.These results are the focus of two published articles (Jaber et al. 2014, ApJ; Lopez-Sepulcre, Jaber et al. 2015, MNRAS), one accepted article (Jaber et al., A&A) and a final article to be submitted (Jaber et al., A&A)
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Kowerko, Danny. "Dynamic Processes in Functionalised Perylene Bisimide Molecules, Semiconductor Nanocrystals and Assemblies." Doctoral thesis, Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-64194.

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Funktionalisierte organische Perylenbisimidfarbstoffe (PBI) und aus Cadmiumselenid bestehende Halbleiternanokristalle werden hinsichtlich physikalischer sowie chemischer Wechselwirkungsprozesse miteinander und mit ihrer Umgebung mittels zeitaufgelöster optischer Spektroskopie untersucht. Im Mittelpunkt der Studien an diesem organisch/anorganischen Modellsystem nanoskopischer Größe steht die Aggregatbildungskinetik und die Identifikation und Quantifizierung von Transferpozessen. Die Anbindung der gut löslichen PBI-Farbstoffe an die Oberfläche solcher Halbleiternanokristalle mittels spezieller Ankergruppen wird durch Selbstorganisation in Lösung realisiert. Die Kombination von Absorptions- und zeitaufgelöster Fluoreszenzspektroskopie zeigt einen unterschiedlich starken Einfluss von Liganden und Farbstoffen auf die Fluoreszenzlöschung der Nanokristalle und belegt, dass Resonanzenergietransfer zum Farbstoff nur in sehr geringem Maße die physikalische Ursache der Fluoreszenzlöschung ist. Die Anzahl adsorbierter Farbstoffe und die Stärke der Fluoreszenzlöschung eines einzelnen Farbstoffmoleküls werden aus zeitaufgelösten Einzelmolekülexperimenten an immobilisierten Emittern gewonnen, welche den direkten spektroskopischen Zugang zur Verteilung gebundener und freier Farbstoffe/Nanokristalle erlaubt. Darüber hinaus werden ankergruppen- und umgebungsspezifische Einflüsse auf die Konformations- und Orientierungsdynamik von Perylenbisimidmolekülen dargestellt. Abschließend werden photo-physikalische Gemeinsamkeiten chemisch unterschiedlich hervorgerufener Fluoreszenzlöschungsprozesse herausgearbeitet und im Kontext von Einzelkristall-Blinkprozessen diskutiert.
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Книги з теми "Molecules and Processes"

1

Theory of multiphoton processes. New York: Plenum Press, 1987.

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2

E, Kingston Arthur, ed. Recent studies in atomic and molecular processes. New York: Plenum Press, 1987.

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ArthurE, Kingston, and Bates David Sir 1916-, eds. Recent advances in atomic and molecular processes. London: Plenum, 1987.

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4

EPS Southern European School of Physics (1st 1991 Avila, Spain). Dynamical processes in molecular physics: First EPS Southern European School of Physics, Avila, Spain, 1-14 September 1991. Edited by Delgado-Barrio G and European Physical Society. Bristol, England: Institute of Physics Pub., 1993.

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1940-, Cantrell C. D., ed. Multiple-photon excitation and dissociation of polyatomic molecules. Berlin: Springer-Verlag, 1986.

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Chowdhury, Debashish. Stochastic Transport in Complex Systems: From Molecules to Vehicles. San Diego: Elsevier Science [Imprint], 2010.

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7

International, Conference on Multiphoton Processes (5th 1990 Paris France). Multiphoton processes: Proceedings of the 5th International Conference on Multiphoton Processes, Paris, France, September, 24-28, 1990. Gif-sur-Yvette [France]: CEA, 1991.

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8

Keith, Evans D., Chin S. L, and International Conference on Multiphoton Processes (6th : 1993 : Ste. Foy, Québec), eds. Multiphoton processes: Proceedings of the 6th international conference, Université Laval, Ste. Foy, Québec, Canada, 25-30 June 1993. Singapore: World Scientific, 1994.

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9

B, Delone N., and Nauchnyĭ sovet po spektroskopii (Akademii͡a︡ nauk SSSR), eds. Mnogofotonnai͡a︡ spektroskopii͡a︡ atomov i molekul. Moskva: Akademii͡a︡ nauk SSSR, Otd-nie obshcheĭ fiziki i astronomii, Nauchnyĭ sovet po spektroskopii, 1989.

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10

D, Bandrauk André, Wallace Stephen C, North Atlantic Treaty Organization. Scientific Affairs Division., and NATO Advanced Research Workshop on Coherence Phenomena in Atoms and Molecules in Laser Fields (1991 : Hamilton, Ont.), eds. Coherence phenomena in atoms and molecules in laser fields. New York: Plenum Press, 1992.

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Частини книг з теми "Molecules and Processes"

1

Kaifu, Norio. "Interstellar Molecules." In Molecular Processes in Space, 205–31. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0591-0_9.

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Ueta, Masayasu, Hiroshi Kanzaki, Koichi Kobayashi, Yutaka Toyozawa, and Eiichi Hanamura. "Theoretical Aspects of Excitonic Molecules." In Excitonic Processes in Solids, 20–115. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82602-3_2.

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3

van Dishoeck, Ewine F. "Photodissociation Processes of Astrophysical Molecules." In Astrochemistry, 51–65. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-4774-0_10.

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4

Ehrhardt, H. "Electron Collisions with Molecules." In Nonequilibrium Processes in Partially Ionized Gases, 19–32. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4615-3780-9_2.

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Billing, Gert Due. "Energy Transfer in Atom/Molecule Collisions with Molecules and Surfaces." In Nonequilibrium Processes in Partially Ionized Gases, 91–104. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4615-3780-9_6.

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Johnson, Philip M. "Resonance Ionization Processes in Small Molecules." In Atomic and Molecular Processes with Short Intense Laser Pulses, 187–94. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0967-3_23.

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Rabitz, Herschel. "Making Molecules Dance: Optimal Control of Molecular Motion." In Atomic and Molecular Processes with Short Intense Laser Pulses, 389–96. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0967-3_47.

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Gershtein, S. S. "Muon Transfer Processes. Old and New Problems." In Muonic Atoms and Molecules, 169–86. Basel: Birkhäuser Basel, 1993. http://dx.doi.org/10.1007/978-3-0348-7271-3_16.

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9

Hall, P. "Modelling Software for Dust Processes." In Dust and Molecules in Evolved Stars, 203–6. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-017-1307-8_28.

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Rouhani, M. Djafari, and D. Estève. "Growth Processes at Surfaces." In Interaction of Atoms and Molecules with Solid Surfaces, 657–72. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-8777-0_19.

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Тези доповідей конференцій з теми "Molecules and Processes"

1

Becker, Uwe. "Photoelectron emission from oriented molecules." In X-RAY AND INNER-SHELL PROCESSES: 18th International Conference. AIP, 2000. http://dx.doi.org/10.1063/1.1302754.

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2

BOHR, HENRIK, PER GREISEN, and BARRY MALIC. "EXCITED STATE PROCESSES IN PHOTOSYNTHESIS MOLECULES." In Proceedings of the 31st International Workshop. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812836625_0034.

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3

SHARIPOV, A. S., and A. V. PELEVKIN. "REACTION KINETICS OF CO AND CH4 MOLECULES WITH O2 IN EXCITED ELECTRONIC STATES: QUANTUM CHEMICAL STUDY." In NONEQUILIBRIUM PROCESSES. TORUS PRESS, 2018. http://dx.doi.org/10.30826/nepcap2018-1-03.

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4

Hill, Jeffrey R., and Dana D. Dlott. "Vibrational Relaxation and Energy Transfer in Ordered and Disordered Molecular Crystals." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/up.1986.tuf2.

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Vibrational energy transfer in condensed phases is a process which occurs on the picosecond time scale. In our lab, we are studying this process in complex molecules in the well-defined environment of a single molecular crystal. We have measured the lifetime of several vibrons in the model system naphthalene, and then extended these studies to several partially deuterated naphthalenes [1,2]. Vibrations in pure crystals form delocalized vibron bands which relax by emission of optical phonons. In disordered or mixed crystals, excited vibrations scatter off impurities and transfer energy to adjacent molecules. Our mixed crystal studies identified these processes. An important question which was raised was the relative importance of two types of relaxation processes. In a one site process, an excited vibration on one molecule decays to a lower vibration in the same molecule by emitting a phonon. In a two site process, the excited vibration decays to a mode on an adjacent molecule. In the naphthalene system, both processes seem to be important.
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Lazar, Mihaela Diana, and Sorina Garabagiu. "Preface: Processes in Isotopes and Molecules (PIM 2013)." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2013). AIP, 2013. http://dx.doi.org/10.1063/1.4833684.

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Lazar, Mihaela D., and Mihaela D. Lazar. "Preface: Processes in Isotopes and Molecules (PIM 2011)." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2011). AIP, 2012. http://dx.doi.org/10.1063/1.3681952.

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7

Kukk, E., A. A. Wills, B. Langer, J. D. Bozek, and N. Berrah. "Angle-resolved 2D imaging of electron emission processes in atoms and molecules." In ATOMIC PROCESSES IN PLASMAS. ASCE, 1998. http://dx.doi.org/10.1063/1.56561.

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Harris, T. D., J. J. Macklin, J. K. Trautman, and L. E. Brus. "Imaging and Time-Resolved Spectroscopy of Single Molecules." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lwd.5.

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Recent progress in the fluorescence detection of individual molecules [1-8] suggests that a single dye molecule can be a useful tool to probe chemical identity and activity. Measurement of fluorescence lifetime [5,6] and spectrum [6] can be augmented by knowledge of molecular orientation using polarized light [3], and triplet [2] and photoisomer excitation, as well as diffusion processes, via fluorescence-intensity correlation. Applications of fluorescent probes include the study of the dynamic conformation of membrane-bound proteins, transport of and signaling by messenger molecules, and the optical detection of the sequence of DNA. While molecules can be spatially located using near-field microscopy [5-8], near-field probes can perturb the molecule under study. We show here that molecular properties can be determined easily and in a non-perturbative manner using far-field illumination, and we obtain unperturbed spectral and lifetime data that cannot be extracted from an ensemble measurement.
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9

Cowan, P. L. "Polarization and anisotropy of x-ray emission from molecules." In X-ray and inner-shell processes. AIP, 1990. http://dx.doi.org/10.1063/1.39854.

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Ma, Y., C. T. Chen, G. Meigs, K. Randall, and F. Sette. "High resolution inner-shell photoabsorption measurements of simple molecules." In X-ray and inner-shell processes. AIP, 1990. http://dx.doi.org/10.1063/1.39840.

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Звіти організацій з теми "Molecules and Processes"

1

McKoy, Vincent. Electrondriven processes in polyatomic molecules. Office of Scientific and Technical Information (OSTI), March 2017. http://dx.doi.org/10.2172/1347212.

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Laurent, Guillaume. Real-time observation of multi-electron processes in atoms and diatomic molecules. Office of Scientific and Technical Information (OSTI), February 2022. http://dx.doi.org/10.2172/1846629.

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Chamovitz, Daniel A., and Zhenbiao Yang. Chemical Genetics of the COP9 Signalosome: Identification of Novel Regulators of Plant Development. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7699844.bard.

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This was an exploratory one-year study to identify chemical regulators of the COP9 signalosome. Chemical Genetics uses small molecules to modify or disrupt the function of specific genes/proteins. This is in contrast to classical genetics, in which mutations disrupt the function of genes. The underlying concept is that the functions of most proteins can be altered by the binding of a chemical, which can be found by screening large libraries for compounds that specifically affect a biological, molecular or biochemical process. In addition to screens for chemicals which inhibit specific biological processes, chemical genetics can also be employed to find inhibitors of specific protein-protein interactions. Small molecules altering protein-protein interactions are valuable tools in probing protein-protein interactions. In this project, we aimed to identify chemicals that disrupt the COP9 signalosome. The CSN is an evolutionarily conserved eight-subunit protein complex whose most studied role is regulation of E3 ubiquitinligase activity. Mutants in subunits of the CSN undergo photomorphogenesis in darkness and accumulate high levels of pigments in both dark- and light-grown seedlings, and are defective in a wide range of important developmental and environmental-response pathways. Our working hypothesis was that specific molecules will interact with the CSN7 protein such that binding to its various interacting proteins will be inhibited. Such a molecule would inhibit either CSN assembly, or binding of CSN-interacting proteins, and thus specifically inhibit CSN function. We used an advanced chemical genetic screen for small-molecule-inhibitors of CSN7 protein-protein interactions. In our pilot study, following the screening of ~1200 unique compounds, we isolated four chemicals which reproducibly interfere with CSN7 binding to either CSN8 or CSN6.
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4

McCurdy, C. William. Ultrafast Processes in Atoms and Molecules: Integrated treatment of electronic and nuclear motion in ultrashort XUV pulses. Office of Scientific and Technical Information (OSTI), December 2017. http://dx.doi.org/10.2172/1413524.

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5

Bhatnagar, R. Infrared and visible laser double resonance studies of vibrational energy transfer processes in polyatomic molecules. [Chromyl chloride solutions]. Office of Scientific and Technical Information (OSTI), January 1991. http://dx.doi.org/10.2172/7265931.

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6

Bhatnagar, R. Infrared and visible laser double resonance studies of vibrational energy transfer processes in polyatomic molecules. Final report, June 15, 1988--June 14, 1991. Office of Scientific and Technical Information (OSTI), December 1991. http://dx.doi.org/10.2172/10176492.

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7

Becker, Kurt H., C. William McCurdy, Thomas M. Orlando, and Thomas N. Rescigno. Current status and future perspectives of electron interactions with molecules, clusters, surfaces, and interfaces [Workshop on Fundamental challenges in electron-driven chemistry; Workshop on Electron-driven processes: Scientific challenges and technological opportunities]. Office of Scientific and Technical Information (OSTI), September 2000. http://dx.doi.org/10.2172/809935.

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8

Leone, Stephen R., and Veronica M. Bierbaum. State Resolved Dynamics of Ion-Molecule Processes. Fort Belvoir, VA: Defense Technical Information Center, February 1998. http://dx.doi.org/10.21236/ada338924.

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Friedman, Shmuel, Jon Wraith, and Dani Or. Geometrical Considerations and Interfacial Processes Affecting Electromagnetic Measurement of Soil Water Content by TDR and Remote Sensing Methods. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7580679.bard.

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Time Domain Reflectometry (TDR) and other in-situ and remote sensing dielectric methods for determining the soil water content had become standard in both research and practice in the last two decades. Limitations of existing dielectric methods in some soils, and introduction of new agricultural measurement devices or approaches based on soil dielectric properties mandate improved understanding of the relationship between the measured effective permittivity (dielectric constant) and the soil water content. Mounting evidence indicates that consideration must be given not only to the volume fractions of soil constituents, as most mixing models assume, but also to soil attributes and ambient temperature in order to reduce errors in interpreting measured effective permittivities. The major objective of the present research project was to investigate the effects of the soil geometrical attributes and interfacial processes (bound water) on the effective permittivity of the soil, and to develop a theoretical frame for improved, soil-specific effective permittivity- water content calibration curves, which are based on easily attainable soil properties. After initializing the experimental investigation of the effective permittivity - water content relationship, we realized that the first step for water content determination by the Time Domain Reflectometry (TDR) method, namely, the TDR measurement of the soil effective permittivity still requires standardization and improvement, and we also made more efforts than originally planned towards this objective. The findings of the BARD project, related to these two consequential steps involved in TDR measurement of the soil water content, are expected to improve the accuracy of soil water content determination by existing in-situ and remote sensing dielectric methods and to help evaluate new water content sensors based on soil electrical properties. A more precise water content determination is expected to result in reduced irrigation levels, a matter which is beneficial first to American and Israeli farmers, and also to hydrologists and environmentalists dealing with production and assessment of contamination hazards of this progressively more precious natural resource. The improved understanding of the way the soil geometrical attributes affect its effective permittivity is expected to contribute to our understanding and predicting capability of other, related soil transport properties such as electrical and thermal conductivity, and diffusion coefficients of solutes and gas molecules. In addition, to the originally planned research activities we also investigated other related problems and made many contributions of short and longer terms benefits. These efforts include: Developing a method and a special TDR probe for using TDR systems to determine also the soil's matric potential; Developing a methodology for utilizing the thermodielectric effect, namely, the variation of the soil's effective permittivity with temperature, to evaluate its specific surface area; Developing a simple method for characterizing particle shape by measuring the repose angle of a granular material avalanching in water; Measurements and characterization of the pore scale, saturation degree - dependent anisotropy factor for electrical and hydraulic conductivities; Studying the dielectric properties of cereal grains towards improved determination of their water content. A reliable evaluation of the soil textural attributes (e.g. the specific surface area mentioned above) and its water content is essential for intensive irrigation and fertilization processes and within extensive precision agriculture management. The findings of the present research project are expected to improve the determination of cereal grain water content by on-line dielectric methods. A precise evaluation of grain water content is essential for pricing and evaluation of drying-before-storage requirements, issues involving energy savings and commercial aspects of major economic importance to the American agriculture. The results and methodologies developed within the above mentioned side studies are expected to be beneficial to also other industrial and environmental practices requiring the water content determination and characterization of granular materials.
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10

Barnett, C. F., H. B. Gilbody, D. C. Gregory, P. M. Griffin, C. C. Havener, A. M. Howald, M. I. Kirkpatrick, E. W. McDaniel, F. W. Meyer, and T. J. Morgan. 1985 bibliography of atomic and molecular processes. Office of Scientific and Technical Information (OSTI), June 1986. http://dx.doi.org/10.2172/5524827.

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