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Journal articles on the topic 'NLO Computation'

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Published: 9 March 2023

Last updated: 10 March 2023

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1

Mulyawan, R. G., A. Salam, and I. Fachruddin. "Bootstrapping Energy-Energy Correlation in Planar 𝓝 = 4 Supersymmetric Yang-Mills." Journal of Physics: Conference Series 2377, no. 1 (November 1, 2022): 012049. http://dx.doi.org/10.1088/1742-6596/2377/1/012049.

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The two-point energy flow correlation, alternatively dubbed the energy-energy correlation (EEC), is a class of conformal field theory observable in the maximally supersymmetric Yang-Mills theory (𝓝 = 4) related to the event shapes in scattering experiments. It has been calculated up to the next-to-leading order (NLO) recently, showcasing the simplicity of the correlation function. This paper calculates the EEC using an approach based on its polylogarithmic functions. Using the amplitude bootstrap method, two ansatzes are made for the energy flow operators, namely the polylogarithm ansatz crafted using the Symbols method, and the polynomial ansatz based on the results from the NLO correction. The computation is carried out in the leading order (LO) and NLO order. After the computation is made, physical constraints are discovered and accordingly applied to the ansatz, namely the symmetry and end-point kinematics constraints. The resulting computation retrieved the energy flow correlation calculated previously using the Mellin-Barnes representation. The non-trivial nature of the result implies a simpler way to calculate the energy flow correlation without the conformal field theory-based approach.

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2

Janjua, Muhammad Ramzan Saeed Ashraf, Zain Hassan Yamani, Saba Jamil, Asif Mahmood, Imran Ahmad, Muhammad Haroon, Mudassir Hussain Tahir, Zhihua Yang, and Shilie Pan. "First Principle Study of Electronic and Non-Linear Optical (NLO) Properties of Triphenylamine Dyes: Interactive Design Computation of New NLO Compounds." Australian Journal of Chemistry 69, no. 4 (2016): 467. http://dx.doi.org/10.1071/ch15402.

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In this study, density functional theory and time-dependent density functional theory are used to determine how the size of π-conjugated system influences the absorption spectra and non-linear optical (NLO) properties of dyes. Double and triple bonds, as well the benzene rings, are used in conjugated systems. The results of the theoretical computation show that the absorption spectra are gradually broadened and red-shifted with increases in the conjugation length. Theoretical examination of the NLO properties was performed on the key parameters of polarizability and hyperpolarizability. A notable increase in the non-linear optical response was observed with an increase in the conjugation length of the π-spacer.

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3

Hu, Ao, Guoyi Yu, Qianjin Wang, Dongxiao Han, Shilun Zhao, Bingqiang Liu, Yu Yu, Yuwen Li, Chao Wang, and Xuecheng Zou. "Efficient Hardware Accelerator Design of Non-Linear Optimization Correlative Scan Matching Algorithm in 2D LiDAR SLAM for Mobile Robots." Sensors 22, no. 22 (November 18, 2022): 8947. http://dx.doi.org/10.3390/s22228947.

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Simultaneous localization and mapping (SLAM) is the major solution for constructing or updating a map of an unknown environment while simultaneously keeping track of a mobile robot’s location. Correlative Scan Matching (CSM) is a scan matching algorithm for obtaining the posterior distribution probability for the robot’s pose in SLAM. This paper combines the non-linear optimization algorithm and CSM algorithm into an NLO-CSM (Non-linear Optimization CSM) algorithm for reducing the computation resources and the amount of computation while ensuring high calculation accuracy, and it presents an efficient hardware accelerator design of the NLO-CSM algorithm for the scan matching in 2D LiDAR SLAM. The proposed NLO-CSM hardware accelerator utilizes pipeline processing and module reusing techniques to achieve low hardware overhead, fast matching, and high energy efficiency. FPGA implementation results show that, at 100 MHz clock, the power consumption of the proposed hardware accelerator is as low as 0.79 W, while it performs a scan match at 8.98 ms and 7.15 mJ per frame. The proposed design outperforms the ARM-A9 dual-core CPU implementation with a 92.74% increase and 90.71% saving in computing speed and energy consumption, respectively. It has also achieved 80.3% LUTs, 84.13% FFs, and 20.83% DSPs saving, as well as an 8.17× increase in frame rate and 96.22% improvement in energy efficiency over a state-of-the-art hardware accelerator design in the literature. ASIC implementation in 65 nm can further reduce the computing time and energy consumption per scan to 5.94 ms and 0.06 mJ, respectively, which shows that the proposed NLO-CSM hardware accelerator design is suitable for resource-limited and energy-constrained mobile and micro robot applications.

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4

Pittau, R. "Recent news and results in the computation of NLO processes with new techniques." Fortschritte der Physik 59, no. 11-12 (May 30, 2011): 1066–69. http://dx.doi.org/10.1002/prop.201100056.

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5

KARAKAŞ, ASLI, ZİYA ERDEM KOÇ, MICHAELA FRIDRICHOVÁ, PETR NĚMEC, and JAN KROUPA. "THE INVESTIGATION OF SECOND-ORDER NONLINEAR OPTICAL PROPERTIES OF P-NITROPHENYLAZOANILINE: SECOND HARMONIC GENERATION AND AB INITIO COMPUTATIONS." Journal of Theoretical and Computational Chemistry 11, no. 01 (February 2012): 209–21. http://dx.doi.org/10.1142/s0219633612500149.

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p-nitrophenylazoaniline (1) belongs to the family of compounds with conjugated bonds and delocalized π-electrons, structurally similar to the well known push-pull compound Disperse Red 1 (DR1).1 Due to the assembly of the molecule, nonlinear optical (NLO) properties are expectable and can be more or less accurately predicted. To estimate the potential for second-order NLO properties, the electric dipole moment (μ), dispersion-free dipole polarizabilities (α) and first hyperpolarizabilities (β) have been determined by density functional theory (DFT) quantum chemical calculations at B3LYP/ 6-311 + G(d, p) level. According to the computation results, the synthesized compound exhibits non-zero β values and it might have second-order NLO behavior. Title compound has been synthesized and characterized by FT-IR, 1H-NMR and UV-Vis spectroscopies. The maximum one-photon absorption (OPA) wavelengths were estimated to be shorter than 450 nm by quantum mechanical computations using the configuration interaction (CI) method. The same result was achieved by UV-Vis spectra measurements, whereas the compound exhibited good optical transparency to the visible light. Quantitative measurements of second harmonic generation (SHG) at 800 nm and 1064 nm have been performed. The relative efficiency comparable with that of KDP (kalium diphosphate) has been observed with the exciting wavelength of 1064 nm, while the other wavelength led to strong absorption of produced light by the sample. In the following more detailed study on frequency-dependent first hyperpolarizabilities using time-dependent Hartree–Fock (TDHF) method have been computed at the wavelengths used in SHG measurements.

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6

Balachandran, V., G. Santhi, V. Karpagam, and A. Lakshmi. "DFT computation and spectroscopic analysis of N-(p-methoxybenzylidene)aniline, a potentially useful NLO material." Journal of Molecular Structure 1047 (September 2013): 249–61. http://dx.doi.org/10.1016/j.molstruc.2013.05.021.

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7

Strickland, Michael. "Non-equilibrium evolution of quarkonium in medium in the open quantum system approach." EPJ Web of Conferences 274 (2022): 01003. http://dx.doi.org/10.1051/epjconf/202227401003.

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In this proceedings contribution, I review recent work that aims to provide a more comprehensive and systematic understanding of bottomonium dynamics in the quark-gluon plasma using an open quantum system (OQS) approach that is applied in the framework of the potential non-relativistic QCD (pNRQCD) effective field theory and coupled to realistic hydrodynamical backgrounds that have been tuned to soft hadron observables. I review how the computation of bottomonium suppression can be reduced to solving a Gorini- Kossakowski-Sudarshan-Lindblad (GKSL) equation for the evolution of the bb̅ reduced density matrix, which includes both singlet and octet states plus medium-induced transitions between them at next-to-leading order (NLO) in the binding energy over temperature. Finally, I present comparisons of phenomenological predictions of the NLO OQS+pNRQCD approach and experimental data for bottomonium suppression and elliptic flow in LHC 5.02 TeV Pb-Pb collisions obtained using both smooth and fluctuating hydrodynamic initial conditions.

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8

Massaro, D., C. Arina, J. Heisig, F. Maltoni, and O. Mattelaer. "Studying dark matter with MadDM: lines and loops." Journal of Physics: Conference Series 2156, no. 1 (December 1, 2021): 012073. http://dx.doi.org/10.1088/1742-6596/2156/1/012073.

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Abstract Automated tools for the computation of amplitudes and cross sections have become the backbone of phenomenological studies beyond the standard model. We present the latest developments in MadDM, a calculator of dark-matter observables based on MadGraph5_aMC@NLO. The new version enables the fully automated computation of loop-induced annihilation processes, relevant for indirect detection of dark matter. Of particular interest is the direct annihilation into photons, γγ, γX. These processes lead to monochromatic gamma-ray lines that are smoking-gun signatures for dark-matter annihilation in our Galaxy. MadDM computes the predictions for the expected photon fluxes near Earth and derives constraints from the gamma-ray line searches by Fermi-LAT and HESS. As an application, we present the implications for the parameter space of the Inert Doublet Model.

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9

Halim, Shimaa Abdel, and Magdy A. Ibrahim. "Simple quantum computation composition, DFT modeling, spectroscopic characterization, and charge, NLO analysis of the novel pyridopyrimidineamide." Journal of Molecular Structure 1251 (March 2022): 132020. http://dx.doi.org/10.1016/j.molstruc.2021.132020.

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10

Kumar, Mohit, Gautam Jaiswar, Mohd Afzal, Mohd Muddassir, Abdullah Alarifi, Aysha Fatima, Nazia Siddiqui, et al. "Quantum Computational, Spectroscopic (FT-IR, FT-Raman, NMR, and UV–Vis) Hirshfeld Surface and Molecular Docking-Dynamics Studies on 5-Hydroxymethyluracil (Monomer and Trimer)." Molecules 28, no. 5 (February 24, 2023): 2116. http://dx.doi.org/10.3390/molecules28052116.

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For many decades, uracil has been an antineoplastic agent used in combination with tegafur to treat various human cancers, including breast, prostate, and liver cancer. Therefore, it is necessary to explore the molecular features of uracil and its derivatives. Herein, the molecule’s 5-hydroxymethyluracil has been thoroughly characterized by NMR, UV–Vis, and FT-IR spectroscopy by means of experimental and theoretical analysis. Density functional theory (DFT) using the B3LYP method at 6-311++G(d,p) was computed to achieve the optimized geometric parameters of the molecule in the ground state. For further investigation and computation of the NLO, NBO, NHO analysis, and FMO, the improved geometrical parameters were utilized. The potential energy distribution was used to allocate the vibrational frequencies using the VEDA 4 program. The NBO study determined the relationship between the donor and acceptor. The molecule’s charge distribution and reactive regions were highlighted using the MEP and Fukui functions. Maps of the hole and electron density distribution in the excited state were generated using the TD-DFT method and PCM solvent model in order to reveal electronic characteristics. The energies and diagrams for the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) were also provided. The HOMO–LUMO band gap estimated the charge transport within the molecule. When examining the intermolecular interactions in 5-HMU, Hirshfeld surface analysis was used, and fingerprint plots were also produced. The molecular docking investigation involved docking 5-HMU with six different protein receptors. Molecular dynamic simulation has given a better idea of the binding of the ligand with protein.

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11

Sainudeen, Zuhail, and Paresh Chandra Ray. "Nonlinear optical properties of ionic NLO chromophores: An attempt to bridge the gap between computation and experiment." International Journal of Quantum Chemistry 105, no. 4 (2005): 348–58. http://dx.doi.org/10.1002/qua.20710.

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12

Bodapati, Ramakrishna, Chakradhar Sahoo, Mahesh Gudem, and Samar K. Das. "Mononuclear Ru(II) Complexes of an Arene and Asymmetrically Substituted 2,2′-Bipyridine Ligands: Photophysics, Computation, and NLO Properties." Inorganic Chemistry 58, no. 17 (August 20, 2019): 11470–79. http://dx.doi.org/10.1021/acs.inorgchem.9b01235.

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13

Kuday, Ayşe Elçi̇boğa, Ferhat Özok, and Erdinç Ulaş Saka. "Probing dark matter via effective field theory approach." International Journal of Geometric Methods in Modern Physics 17, no. 02 (January 31, 2020): 2050028. http://dx.doi.org/10.1142/s0219887820500280.

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We analyze dark matter in most general form of effective field theory approach. To examine the interactions between the weakly interacting massive particles (WIMPs) and the Standard Model (SM) particles, we use the six-dimensional EFT mediated by new physics scale [Formula: see text] at tree level. After implementing a new effective field theory model in FeynRules [FeynRules 2.0 A complete toolbox for tree-level phenomenology, Comput. Phys. Comm. 185(8) (2014) 2250–2300] We investigate the theory and constrain the theory by using relic density generated by MadDM [MadDM v.3.0: A Comprehensive tool for dark matter studies, Phys. Dark Univ. 24 (2019) 100249] tool of MadGraph5_aMC@NLO [The automated computation of tree-level and next-to-leading order differential cross-sections, and their matching to parton shower simulations, J. High Energy Phys. 79 (2014) 2014].

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14

Janjua, Muhammad Ramzan Saeed Ashraf. "First theoretical framework of di-substituted donor moieties of triphenylamine and carbazole for NLO properties: quantum paradigms of interactive molecular computation." Molecular Simulation 43, no. 18 (June 5, 2017): 1539–45. http://dx.doi.org/10.1080/08927022.2017.1332413.

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15

Fadhul, Zainab S. M. M. M., Eman A. H. F. Ali, Shivaraj R. Maidur, Parutagouda Shankaragouda Patil, M. Shkir, and Fryad Z. Henari. "Thermally induced optical nonlinearity and optical power limiting action of 2,4,5-trimethoxy-4′-nitrochalcone under CW laser regime." Journal of Nonlinear Optical Physics & Materials 27, no. 01 (March 2018): 1850012. http://dx.doi.org/10.1142/s0218863518500121.

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In the present work, we report the results of thermally induced third-order nonlinear optical (NLO) properties of 2,4,5-trimethoxy-4[Formula: see text]-nitrochalcone (abbreviated as 2,4,5TMNC) investigated by [Formula: see text]-scan technique using continuous wave (CW) Argon ion laser at a wavelength of 488[Formula: see text]nm with adjusted power ranging from 2.5[Formula: see text]mW to 20[Formula: see text]mW. The experiments were performed by varying the concentration of the molecules in solution. The sample demonstrated strong reverse saturable absorption (RSA) and self-defocusing effect (negative nonlinear refractive index). The estimated values of the NLO absorption coefficient ([Formula: see text], nonlinear refraction ([Formula: see text] and absolute nonlinear susceptibility [Formula: see text] are found to be of the order of 10[Formula: see text][Formula: see text]m/W, 10[Formula: see text][Formula: see text]m2/W and 10[Formula: see text][Formula: see text]esu, respectively. The magnitude of the nonlinear absorption coefficient ([Formula: see text] was found to increase with concentration. The linear absorption spectrum of 2,4,5TMNC was measured using UV–Vis–NIR spectrometer. The optical band gap (Eg) value of title chalcone is obtained from the tauc’s plot of ([Formula: see text] versus [Formula: see text]. The optical limiting performance of 2,4,5TMNC is also investigated for device application. In addition to the above, the computation studies are also carried out to attain the ground state molecular geometry which is found in close to experimental results. Time-Dependent- Density Function Theory (TD-DFT) was used to determine the UV–Vis spectrum at B3LYP/6-31G* level of theory and found to be comparable with experimental data. The HOMO–LUMO energy gap was also determined and discussed. The results promote this chalcone derivative as a promising candidate for optical limiting and optical switching applications.

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16

Sukanya, R., D. Aruldhas, I. Hubert Joe, and S. Balachandran. "Spectroscopic and quantum chemical computation on molecular structure, AIM, ELF, RDG, NCI, and NLO activity of 4-VINYL benzoic acid: A DFT approach." Journal of Molecular Structure 1253 (April 2022): 132273. http://dx.doi.org/10.1016/j.molstruc.2021.132273.

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17

Venkatesan, Perumal, Subbiah Thamotharan, Andivelu Ilangovan, Hongze Liang, and Tom Sundius. "Crystal structure, Hirshfeld surfaces and DFT computation of NLO active (2E)-2-(ethoxycarbonyl)-3-[(1-methoxy-1-oxo-3-phenylpropan-2-yl)amino] prop-2-enoic acid." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 153 (January 2016): 625–36. http://dx.doi.org/10.1016/j.saa.2015.09.002.

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18

Singh, Pratibha, Amit Kumar, Reena, Archana Gupta, Parutagouda Shankaragouda Patil, Shriganesh Prabhu, and C. S. Garde. "Vibrational spectroscopic characterization, electronic absorption, optical nonlinearity computation and terahertz investigation of (2E) 3-(4-ethoxyphenyl)-1-(3-bromophenyl) prop-2-en-1-one for NLO device fabrication." Journal of Molecular Structure 1198 (December 2019): 126909. http://dx.doi.org/10.1016/j.molstruc.2019.126909.

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19

Gobinath, E., and R. John Xavier. "Quantum chemical computations, vibrational spectroscopic studies, NLO and NBO/NLMO analysis of o-chlorobenzohydrazide." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 129 (August 2014): 14–21. http://dx.doi.org/10.1016/j.saa.2014.03.026.

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20

Balaji, N., M. R. Kannan, Y. Sheeba Sherlin, and T. Vijayakumar. "Quantum Chemical Computations of an Efficient Push-Pull NLO Chromophore 3-[4-Nitrophenyl Azo]- 9H- Carbazole-9-Ethanol." IOP Conference Series: Materials Science and Engineering 1219, no. 1 (January 1, 2022): 012023. http://dx.doi.org/10.1088/1757-899x/1219/1/012023.

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Abstract Electric-optic (EO) materials are being explored for applications ranging from fiber and satellite telecommunications, optical gyroscopes, to photonic detection of radar etc. Dipolar push-pull Organic chromophores that exhibit extended π-conjugation, in particular, show enhanced second order NLO properties. The present investigation reports the quantum chemical computations of the high efficiency push-pull NLO molecule 3-[(4-Nitrophenyl Azo)] - 9H-Carbazole-9-Ethanol (NPACE). The organic push-pull molecule is optimized in gaseous and in various solvent condition using Exchange correlation function (B3LYP/MP2). Molecular electrostatic potential, thermal properties and NBO analysis have also been performed in detail. The effective electron cloud moment in the molecule is mainly governed by the physical process termed intramolecular Charge Transfer (ICT).

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21

Nagy, Zoltán, and Davison E. Soper. "Matching parton showers to NLO computations." Journal of High Energy Physics 2005, no. 10 (October 10, 2005): 024. http://dx.doi.org/10.1088/1126-6708/2005/10/024.

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22

Azaid, A., T. Abram, R. Kacimi, M. Raftani, Y. Khaddam, D. Nebbach, A. Sbai, T. Lakhlifi, and M. Bouachrine. "Nonlinear optical response of D-π-A chromophores based on benzoxazin: quantum modification of π‑spacer." Current Chemistry Letters 11, no. 3 (2022): 331–40. http://dx.doi.org/10.5267/j.ccl.2022.3.001.

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In this research article, four chromophores based on benzoxazine as the electron donor and tricyanovinyl dihydrofuran (TCF) as the electron acceptor have been designed to investigate the nonlinear optical (NLO) response. The geometric and electronic structures, absorption spectra, NBO analysis, and nonlinear optical response have been calculated by employing density functional theory (DFT) at PBEPBE/6-31G (d,p). The new design of chromophores has been proposed by the structural modification of π-spacers/conjugated systems. The DFT and TD−DFT computations at CAM−B3LYP/6−31G (d,p) have been performed to shed light on the influences of structural modification on the NLO properties. The absorption wavelength in different organic solvents, polarizability (α), and hyperpolarizability (β) are all determined. A strong NLO response indicates that this family of organic compounds with a D-π-A structure exhibits large first hyperpolarizability βtot values, these values are much greater than ones of urea. This theoretical model may be used to design other chromophores for usage in electro-optics.

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23

Khalid, Muhammad, Muhammad Usman Khan, Iqra Shafiq, Riaz Hussain, Akbar Ali, Muhammad Imran, Ataualpa A. C. Braga, Muhammad Fayyaz ur Rehman, and Muhammad Safwan Akram. "Structural modulation of π-conjugated linkers in D–π–A dyes based on triphenylamine dicyanovinylene framework to explore the NLO properties." Royal Society Open Science 8, no. 8 (August 2021): 210570. http://dx.doi.org/10.1098/rsos.210570.

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A donor–π–acceptor type series of Triphenylamine–dicyanovinylene-based chromophores ( DPMN1–DPMN11 ) was designed theoretically by the structural tailoring of π-linkers of experimentally synthesized molecules DTTh and DTTz to exploit changes in the optical properties and their nonlinear optical materials (NLO) behaviour. Density functional theory (DFT) computations were employed to understand the electronic structures, absorption spectra, charge transfer phenomena and the influence of these structural modifications on NLO properties. Interestingly, all investigated chromophores exhibited lower band gap (2.22–2.60 eV) with broad absorption spectra in the visible region, reflecting the remarkable NLO response. Furthermore, natural bond orbital (NBO) findings revealed a strong push–pull mechanism in DPMN1–DPMN11 as donor and π-conjugates exhibited positive, while all acceptors showed negative values. Examination of electronic transitions from donor to acceptor moieties via π-conjugated linkers revealed greater linear (〈 α 〉 = 526.536–641.756 a.u.) and nonlinear ( β tot = 51 313.8–314 412.661 a.u.) response. It was noted that the chromophores containing imidazole in the second p-linker expressed greater hyperpolarizability when compared with the ones containing pyrrole. This study reveals that by controlling the type of π-spacers, interesting metal-free NLO materials can be designed, which can be valuable for the hi-tech NLO applications.

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24

Serdaroglu, Goncagul, and Nesimi Uludag. "Concise total synthesis of (±)-aspidospermidine and computational study: FT-IR, NMR, NBO, NLO, FMO, MEP diagrams." Journal of Molecular Structure 1166 (August 2018): 286–303. http://dx.doi.org/10.1016/j.molstruc.2018.04.050.

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25

DU, XIAOFENG, NANA MA, SHILING SUN, HAIMING XIE, and YONGQING QIU. "THEORETICAL INVESTIGATION ON PHOTOISOMERIZATION SWITCHABLE SECOND-ORDER NONLINEAR OPTICAL PROPERTIES OF Λ-SHAPED DIARYLETHENE DERIVATIVES." Journal of Theoretical and Computational Chemistry 12, no. 04 (June 2013): 1350029. http://dx.doi.org/10.1142/s0219633613500296.

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The nonlinear optical (NLO) properties of Λ-shaped diarylethene (DAE) derivatives 1a(b)–4a(b) and their NLO switching effects were studied by using the density functional theory (DFT) methods. The results demonstrate that all of the open-ring molecules and their own closed-ring forms meet the model of NLO switching tuned by photoisomerization. The βtot values of 1b–3b are 16 times as small as that of their open-ring forms, and βtot value of 4b is 4 times as large as that of 4a. The spin interactions of open-shell closed-ring molecules are larger than that of their open-ring forms, and it could increase the NLO responses to some degree. Nature bond orbital (NBO) calculations indicate that large charge differences between electron-deficient and electron-rich centers are beneficial to charge transfer (CT), and the overlap between frontier molecular orbital (FMO) is also advantageous to the CT and NLO responses. Time-dependent density functional theory (TD-DFT) calculations show βtot values of all molecules meet the two-level model very well, and the smaller the ΔE ge , the larger the βtot value.

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26

Frixione, Stefano, and Bryan R. Webber. "Matching NLO QCD computations and parton shower simulations." Journal of High Energy Physics 2002, no. 06 (June 12, 2002): 029. http://dx.doi.org/10.1088/1126-6708/2002/06/029.

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27

Protonotarios, Nicholas E., Athanassios S. Fokas, Kostas Kostarelos, and George A. Kastis. "The attenuated spline reconstruction technique for single photon emission computed tomography." Journal of The Royal Society Interface 15, no. 148 (November 2018): 20180509. http://dx.doi.org/10.1098/rsif.2018.0509.

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We present the attenuated spline reconstruction technique (aSRT) which provides an innovative algorithm for single photon emission computed tomography (SPECT) image reconstruction. aSRT is based on an analytic formula of the inverse attenuated Radon transform. It involves the computation of the Hilbert transforms of the linear attenuation function and of two sinusoidal functions of the so-called attenuated sinogram . These computations are achieved by employing the attenuation information provided by computed tomography (CT) scans and by utilizing custom-made cubic spline interpolation. The purpose of this work is: (i) to present the mathematics of aSRT, (ii) to reconstruct simulated and real SPECT/CT data using aSRT and (iii) to evaluate aSRT by comparing it to filtered backprojection (FBP) and to ordered subsets expectation minimization (OSEM) reconstruction algorithms. Simulation studies were performed by using an image quality phantom and an appropriate attenuation map. Reconstructed images were generated for 45, 90 and 180 views over 360 degrees with 20 realizations and involved Poisson noise of three different levels (NL), namely 100% (NL1), 50% (NL2) and 10% (NL3) of the total counts, respectively. Moreover, real attenuated SPECT sinograms were reconstructed from a real study of a Jaszczak phantom, as well as from a real clinical myocardial SPECT/CT study. Comparisons between aSRT, FBP and OSEM reconstructions were performed using contrast, bias and image roughness. The results suggest that aSRT can efficiently produce accurate attenuation-corrected reconstructions for simulated and real phantoms, as well as for clinical data. In particular, in the case of the clinical myocardial study, aSRT produced reconstructions with higher cold contrast than both FBP and OSEM. aSRT, by incorporating the attenuation correction within itself, may provide an improved alternative to FBP. This is particularly promising for ‘cold’ regions as those occurring in myocardial ischaemia.

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SRIKANTH, KATTAESWAR, RAMAIAH KONAKANCHI, and JYOTHI PRASHANTH. "A Combined Experimental (FT-IR) and Computational Studies of 9-Chloroanthracene." Asian Journal of Chemistry 31, no. 6 (April 29, 2019): 1332–42. http://dx.doi.org/10.14233/ajchem.2019.21928.

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The experimental FT-IR spectral analysis of 9-chloroanthracene has worked out by using density functional theory (DFT). The optimized molecular structure and minimum energy of 9-chloroanthracene has analyzed using DFT/B3LYP functional employing 6-311++G(d,p) basis set. The vibrational frequencies along with IR intensities were computed, scaling was used for a better fit between the experimental and computed frequencies, they agreed with rms error 8.48 cm-1 for 9-chloroanthracene. The NLO behaviour of the molecule is investigated from first-order hyperpolarizability. The HOMO and LUMO energies are evaluated to demonstrate the chemical stability, reactivity of molecule. The MESP over the molecules were plotted to evaluate electron density regions and thermodynamic parameters are calculated. Hyper conjugative interactions and charge delocalization of the molecule study from NBO analysis and Fukui functions are evaluated for 9-chloroanthracene. The molecular docking studies were performed against anticancer protein targets Tyrosinase and HER2.

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29

Serdaroğlu, G., and N. Uludağ. "Spectroscopic (FT-IR, NMR) and Computational Investigation of 2-(2-Aminoethyl)-1,2,3,4,9-Tetrahydrocarbazole: NBO, NLO, FMO, MEP Analysis." Journal of Structural Chemistry 60, no. 8 (August 2019): 1267–84. http://dx.doi.org/10.1134/s0022476619080079.

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30

Xavier, S., S. Periandy, and S. Ramalingam. "NBO, conformational, NLO, HOMO–LUMO, NMR and electronic spectral study on 1-phenyl-1-propanol by quantum computational methods." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 137 (February 2015): 306–20. http://dx.doi.org/10.1016/j.saa.2014.08.039.

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31

Sana Mazhar, Sana Mazhar, Muhammad Khalid Muhammad Khalid, Muhammad Nawaz Tahir Muhammad Nawaz Tahir, Muhammad Haroon Muhammad Haroon, Tashfeen Akhtar Tashfeen Akhtar, Muhammad Usman Khan Muhammad Usman Khan, Farrukh Jaleel Farrukh Jaleel, and Muhammad Aslam Muhammad Aslam. "Facile Synthesis, Crystal Growth, Quantum Chemical Studies of Electronic Structure and of the Profoundly Persuasive NLO Organic Crystal: Ethyl 4-[N,N-bis(p-toluenesulfonyl)]- Aminobenzoate." Journal of the chemical society of pakistan 41, no. 1 (2019): 122. http://dx.doi.org/10.52568/000713/jcsp/41.01.2019.

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In the present work, we synthesized Ethyl-4-[N,N-bis (p-toluene sulfonyl)amino]benzoate crystal and structurally characterized by X-ray diffraction (XRD) method. The optimized geometry and vibration wave numbers of the compound investigated was obtained by performing density functional theory (DFT) computations at the M06-2X level of theory and with the 6-311+G(d,p) basis set. The DFT findings show good agreement with the experimental XRD data. Natural bond orbital (NBO) study was performed at the M06-2X/6-311+G(d,p) level to find the stability due to charge delocalization and hyperconjugative interactions. Charge transfer properties and chemical activities at different sites of the synthesized compound was quantitatively determined by performing frontier molecular orbital (FMO) analysis and molecular electrostatic potential (MEP) surfaces at the M06-2X level of theory with 6-311+G(d,p) basis set. The global reactivity parameters were explored with use of the energy of the FMOs. These descriptors predicted the stability of the investigated molecule by revealing the larger hardness and less softness values. Nonlinear optical (NLO) properties was computed at the M06-2X level of theory and 6-311+G(d,p) basis set combination which is observed larger as compared to the urea molecule indicating the considerable NLO character.

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32

Abbaz, Tahar, Amel Bendjeddou, and Didier Villemin. "Structure, electronic properties, NBO, NLO and chemi-cal reactivity of bis (1, 4-dithiafulvalene) derivatives: functional density theory study." International Journal of Advanced Chemistry 6, no. 1 (December 20, 2017): 18. http://dx.doi.org/10.14419/ijac.v6i1.8668.

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In this work, through computational study based on density functional theory (DFT/B3LYP) using basis set 6-31G (d,p) a number of global and local reactivity descriptors for a series of molecules containing a TTF function which are bis (1,4-dithiafulvalene) derivatives. They were computed to predict the reactivity and the reactive sites on the molecules. The molecular geometry and the electronic properties in the ground state such as frontier molecular orbital (HOMO and LUMO), ionization potential (I) and electron affinity (A) were investigated to get a better insight of the molecular properties. Molecular electrostatic potential (MEP) for all compounds were determined to check their electrophilic or nucleophilic reactivity. Fukui index, polarizability, hyperpolarizability, second order NLO property and natural bond orbital (NBO) analyses have also employed to determine the reactivity of bis (1,4-dithiafulvalene) derivatives.

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Attar, Salahuddin S., Luciano Marchiò, Luca Pilia, Maria F. Casula, Davide Espa, Angela Serpe, Maddalena Pizzotti, Daniele Marinotto, and Paola Deplano. "Design of nickel donor–acceptor dithiolenes for 2nd order nonlinear optics: an experimental and computational study." New Journal of Chemistry 43, no. 32 (2019): 12570–79. http://dx.doi.org/10.1039/c9nj02976a.

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This study, concerning the influence on the NLO properties of a remote functionality in the donor of D–Ni–A dithiolenes 1–4, allows to point out the relationship between NLO properties and the donor capability in modulating the low-energy absorption.

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34

Tedjeuguim, Charly Tsapi, Stanley Numbonui Tasheh, and Ghogomu Julius Numbonui. "Theoretical Investigation of the Nonlinear Optical and Charge Transport Properties of N-(4-Methoxybenzylidene) Isonicotinohydrazone and Some of Its Derivatives: A DFT and TD-DFT Study." Advances in Materials Science and Engineering 2023 (January 16, 2023): 1–14. http://dx.doi.org/10.1155/2023/6588603.

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Here, we report the findings from a study on the charge transport and nonlinear optical (NLO) properties of N-(4-methoxybenzylidene) isonicotinohydrazone (INH) and some of its derivatives named INH1-INH15. The density functional theory (DFT) approach was used for ground state computations at the B3LYP-D/6-311G (d,p) level of theory, while the time-dependent density functional theory (TD-DFT) was carried out at the CAM-B3LYP/6-311G (d,p) level. The results show that the energy gaps of all the studied compounds range from 3.933 to 4.645 eV. INH3 and INH4 have the lowest electron and hole reorganization energies (i.e., 0.409 and 0.634 eV, respectively) and can thus be classified as moderate electron and hole-carrying materials for organic light-emitting diode (OLED) applications. TD-DFT computations demonstrate that an extension of the conjugation (in INH2 and INH3) increases the oscillator strength, improving the NLO response. According to the NLO data, INH2 and INH3 have higher static isotropic polarizabilities (38.509 and 37.986 × 10−24 esu, respectively) and second hyperpolarizabilities (54.440 and 57.598 × 10−36 esu, respectively), while INH4 and INH13 have higher first hyperpolarizability values (11.944 and 10.939 × 10−30 esu, respectively). The results reveal that INH derivatives with different groups are viable alternatives for OLED and NLO applications.

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35

Montero, G., L. González, E. Flórez, M. D. García, and A. Suárez. "Approximate inverse computation using Frobenius inner product." Numerical Linear Algebra with Applications 9, no. 3 (February 13, 2002): 239–47. http://dx.doi.org/10.1002/nla.269.

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36

Jiang, Xingxing, Lei Kang, Siyang Luo, Pifu Gong, Ming-Hsien Lee, and Zheshuai Lin. "Development of nonlinear optical materials promoted by density functional theory simulations." International Journal of Modern Physics B 28, no. 27 (October 30, 2014): 1430018. http://dx.doi.org/10.1142/s0217979214300187.

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Nonlinear optical (NLO) crystals are very important optoelectronic functional materials and their developments have significantly contributed to the progress of laser science and technology for decades. In order to explore new NLO crystals with superior performances, it is greatly desirable to understand the intrinsic relationship between the macroscopic optical properties and microscopic structural features in crystals. In this paper, the applications of density functional theory (DFT) method to the elucidation of the structure-property relationship and to the exploration on novel NLO materials in the ultraviolet and infrared spectrum regions are reviewed. The great success in the linear and NLO property predictions has been achieved using the first-principles computational simulations, and the mechanism understanding obtained by various analysis tools can give substantial guidance to the search and design of new NLO crystals.

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37

Delgado, Jorge, Héctor Orera, and Juan Manuel Peña. "Accurate computations with Laguerre matrices." Numerical Linear Algebra with Applications 26, no. 1 (October 5, 2018): e2217. http://dx.doi.org/10.1002/nla.2217.

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38

Axelsson, Owe, and Xiaojun Chen. "Matrix computations and nonlinear equations." Numerical Linear Algebra with Applications 18, no. 2 (February 21, 2011): 175–76. http://dx.doi.org/10.1002/nla.773.

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39

Frixione, Stefano, Paolo Nason, and Carlo Oleari. "Matching NLO QCD computations with parton shower simulations: the POWHEG method." Journal of High Energy Physics 2007, no. 11 (November 23, 2007): 070. http://dx.doi.org/10.1088/1126-6708/2007/11/070.

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40

Zahid, Saba, Alvina Rasool, Ali Raza Ayub, Khurshid Ayub, Javed Iqbal, M. S. Al-Buriahi, Norah Alwadai, and H. H. Somaily. "Silver cluster doped graphyne (GY) with outstanding non-linear optical properties." RSC Advances 12, no. 9 (2022): 5466–82. http://dx.doi.org/10.1039/d1ra08117a.

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41

Chu, Delin. "On the computation of the infimum inH∞-optimization." Numerical Linear Algebra with Applications 11, no. 7 (August 11, 2004): 619–48. http://dx.doi.org/10.1002/nla.367.

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42

Demircioğlu, Zeynep, Çiğdem Albayrak Kaştaş, and Orhan Büyükgüngör. "X-ray structural, spectroscopic and computational approach (NBO, MEP, NLO, NPA, fukui function analyses) of (E)-2-((4-bromophenylimino)methyl)-3-methoxyphenol." Molecular Crystals and Liquid Crystals 656, no. 1 (October 13, 2017): 169–84. http://dx.doi.org/10.1080/15421406.2017.1405660.

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43

Sirković, Petar. "A reduced basis approach to large-scale pseudospectra computation." Numerical Linear Algebra with Applications 26, no. 2 (October 25, 2018): e2222. http://dx.doi.org/10.1002/nla.2222.

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Oseledets, I. V., D. V. Savostyanov, and E. E. Tyrtyshnikov. "Cross approximation in tensor electron density computations." Numerical Linear Algebra with Applications 17, no. 6 (November 26, 2010): 935–52. http://dx.doi.org/10.1002/nla.682.

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45

Liu, Yidan, Yizhong Yuan, Xiaohui Tian, Jianyong Yuan, and Jinyu Sun. "Computational design of p-(dimethylamino)benzylidene-derived push–pull polyenes with high first-hyperpolarizabilities." Physical Chemistry Chemical Physics 22, no. 9 (2020): 5090–104. http://dx.doi.org/10.1039/c9cp05631a.

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46

Sharma, Anshuman, Abdul Hafeez Syed, Midhun M, and M. R. Raghavendra. "Realization of Programmable BPSK Demodulator-Bit Synchronizer using Multirate Processing." International Journal of Reconfigurable and Embedded Systems (IJRES) 3, no. 1 (March 1, 2014): 18. http://dx.doi.org/10.11591/ijres.v3.i1.pp18-24.

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This paper presents the design and implementation of programmable BPSK demodulator and bit synchronizer. The demodulator is based on the Costas loop design whereas the bit synchronizer is based on Gardner timing error detector. The advantage of this design is that it offers programmability using multi-rate processing and does not rely on computation of filter coefficients, NCO angle input for each specific data rate and thus avoids computational complexities. The algorithm and its application were verified on Matlab-Simulink and were implemented on ALTERA platform. A 32 kHz BPSK demodulator–bit synchronizer pair catering for a data rate from 1kbps to 8kbps was implemented.

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47

GARCÍA, MANUEL J., MIGUEL A. HENAO, and OSCAR E. RUIZ. "FIXED GRID FINITE ELEMENT ANALYSIS FOR 3D STRUCTURAL PROBLEMS." International Journal of Computational Methods 02, no. 04 (December 2005): 569–86. http://dx.doi.org/10.1142/s0219876205000582.

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Fixed Grid (FG) methodology was first introduced by García and Steven as an engine for numerical estimation of two-dimensional elasticity problems. The advantages of using FG are simplicity and speed at a permissible level of accuracy. Two-dimensional FG has been proved effective in approximating the strain and stress field with low requirements of time and computational resources. Moreover, FG has been used as the analytical kernel for different structural optimization methods as Evolutionary Structural Optimization, Genetic Algorithms (GA), and Evolutionary Strategies. FG consists of dividing the bounding box of the topology of an object into a set of equally sized cubic elements. Elements are assessed to be inside (I), outside (O) or neither inside nor outside (NIO) of the object. Different material properties assigned to the inside and outside medium transform the problem into a multi-material elasticity problem. As a result of the subdivision NIO elements have non-continuous properties. They can be approximated in different ways which range from simple setting of NIO elements as O to complex non-continuous domain integration. If homogeneously averaged material properties are used to approximate the NIO element, the element stiffness matrix can be computed as a factor of a standard stiffness matrix thus reducing the computational cost of creating the global stiffness matrix. An additional advantage of FG is found when accomplishing re-analysis, since there is no need to recompute the whole stiffness matrix when the geometry changes. This article presents CAD to FG conversion and the stiffness matrix computation based on non-continuous elements. In addition inclusion/exclusion of O elements in the global stiffness matrix is studied. Preliminary results shown that non-continuous NIO elements improve the accuracy of the results with considerable savings in time. Numerical examples are presented to illustrate the possibilities of the method.

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48

Mubarik, Adeel, Nasir Rasool, Muhammad Ali Hashmi, Asim Mansha, Muhammad Zubair, Mohammed Rafi Shaik, Mohammed A. F. Sharaf, Emad Mahrous Awwad, and Abdelatty Abdelgawad. "Computational Study of Structural, Molecular Orbitals, Optical and Thermodynamic Parameters of Thiophene Sulfonamide Derivatives." Crystals 11, no. 2 (February 20, 2021): 211. http://dx.doi.org/10.3390/cryst11020211.

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Thiophene and sulfonamide derivatives serve as biologically active compounds, used for the manufacture of large numbers of new drugs. In this study, 11 selected derivatives of thiophene sulfonamide were computed for their geometric parameters, such as hyperpolarizability, chemical hardness (ƞ), electronic chemical potential (μ), electrophilicity index (ω), ionization potential (I), and electron affinity (A). In addition, FT-IR and UV-Vis spectra were also simulated through theoretical calculations. The geometrical parameters and vibrational frequencies with assignments of the vibrational spectra strongly resemble the experimentally calculated values. Besides, the frontier molecular orbitals were also determined for various intramolecular interactions that are responsible for the stability of the compounds. The isodensity surfaces of the frontier molecular orbitals (FMOs) are the same pattern in most of the compounds, but in some compounds are disturbed due to the presence of highly electronegative hetero-atoms. In this series of compounds, 3 shows the highest HOMO–LUMO energy gap and lowest hyperpolarizability, which leads to the most stable compound and less response to nonlinear optical (NLO), while 7 shows the lowest HOMO–LUMO energy gap and highest hyperpolarizability, which leads to a less stable compound and a high NLO response. All compounds have their extended three-dimensional p-electronic delocalization which plays an important role in studying NLO responses.

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Liu, Chun-Guang, Ming-Li Gao, and Zhi-Jian Wu. "Computational study on redox-switchable second-order nonlinear optical properties of ferrocene-tetrathiafulvalene hybrid." RSC Adv. 4, no. 72 (2014): 38300–38309. http://dx.doi.org/10.1039/c4ra04548c.

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Wang, Lei, Heng Liang, Fengshan Bai, and Yan Huo. "A load balancing strategy for parallel computation of sparse permanents." Numerical Linear Algebra with Applications 19, no. 6 (June 22, 2012): 1017–30. http://dx.doi.org/10.1002/nla.1844.

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