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2. Diagnostics of molecular orbital quality

Author

Deng, Jia, Gilbert, Andrew T.B., and Gill, Peter M.W.

Subjects
Molecular orbitals -- Measurement -- Research, Quantum chemistry -- Research -- Measurement, Chemistry
Abstract

We discuss several measures of the quality of a molecular orbital. Each requires only that the orbital be associated with a well-defined Fock operator and is thus applicable to both Hartree-Fock and density functional orbitals. One of the measures, the γ diagnostic, ranges from γ = 0 (perfect) to γ = π/2 (poor) and is conceptually simple. We illustrate its usefulness by applying it to a number of small atoms and ions. Key words: molecular orbital quality, density functional theory, Hartree-Fock. On discute de plusieurs mesures de la qualite d'une orbitale moleeculaire. Chacune necessite uniquement que l'orbitale soit associeea un opeerateur de Fock bien defini et qu'il soit ainsi applicable aux orbitales de Hartree-Fock ainsi qu'aux fonctionnelles de densite. L'une ce ces mesures, le diagnostic, s'etend de 0 (parfait) a 2 (mauvais) et elle est conceptuellement simple. On illustre son utilite en l'appliquant a un certain nombre de petits atomes et de petits ions. Mots-cles: qualite d'une orbitale moleculaire, theeorie de la fonctionnelle de la densite, Hartree-Fock. [Traduit par la Redaction], Introduction Some say that quantum chemistry is a branch of applied mathematics and that, by implication, quantum chemists are applied mathematicians. One can certainly mount a strong argument in favor [...]

Published
2010
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3. BFW: A density functional for transition metal clusters

Author

Addicoat, Matthew A., Buntine, Mark A., Metha, Gregory F., Gilbert, Andrew T.B., and Gill, Peter M.W.

Subjects
Density functionals -- Usage, Transition metal compounds -- Chemical properties, Carbides -- Chemical properties, Nitrides -- Chemical properties, Oxides -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

A new density functional (BFW) is introduced which is explicitly designed to yield accurate, absolute ionization potentials for transition metal clusters. The numerical results for a selection of transition metal clusters and their carbides, nitrides and oxides are presented and at the same time it is found that BFW functional is significantly more accurate than B3LYP and B3PW91.

Published
2007

6. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

Author

Shao, Yihan, primary, Gan, Zhengting, additional, Epifanovsky, Evgeny, additional, Gilbert, Andrew T.B., additional, Wormit, Michael, additional, Kussmann, Joerg, additional, Lange, Adrian W., additional, Behn, Andrew, additional, Deng, Jia, additional, Feng, Xintian, additional, Ghosh, Debashree, additional, Goldey, Matthew, additional, Horn, Paul R., additional, Jacobson, Leif D., additional, Kaliman, Ilya, additional, Khaliullin, Rustam Z., additional, Kuś, Tomasz, additional, Landau, Arie, additional, Liu, Jie, additional, Proynov, Emil I., additional, Rhee, Young Min, additional, Richard, Ryan M., additional, Rohrdanz, Mary A., additional, Steele, Ryan P., additional, Sundstrom, Eric J., additional, Woodcock, H. Lee, additional, Zimmerman, Paul M., additional, Zuev, Dmitry, additional, Albrecht, Ben, additional, Alguire, Ethan, additional, Austin, Brian, additional, Beran, Gregory J. O., additional, Bernard, Yves A., additional, Berquist, Eric, additional, Brandhorst, Kai, additional, Bravaya, Ksenia B., additional, Brown, Shawn T., additional, Casanova, David, additional, Chang, Chun-Min, additional, Chen, Yunqing, additional, Chien, Siu Hung, additional, Closser, Kristina D., additional, Crittenden, Deborah L., additional, Diedenhofen, Michael, additional, DiStasio, Robert A., additional, Do, Hainam, additional, Dutoi, Anthony D., additional, Edgar, Richard G., additional, Fatehi, Shervin, additional, Fusti-Molnar, Laszlo, additional, Ghysels, An, additional, Golubeva-Zadorozhnaya, Anna, additional, Gomes, Joseph, additional, Hanson-Heine, Magnus W.D., additional, Harbach, Philipp H.P., additional, Hauser, Andreas W., additional, Hohenstein, Edward G., additional, Holden, Zachary C., additional, Jagau, Thomas-C., additional, Ji, Hyunjun, additional, Kaduk, Benjamin, additional, Khistyaev, Kirill, additional, Kim, Jaehoon, additional, Kim, Jihan, additional, King, Rollin A., additional, Klunzinger, Phil, additional, Kosenkov, Dmytro, additional, Kowalczyk, Tim, additional, Krauter, Caroline M., additional, Lao, Ka Un, additional, Laurent, Adèle D., additional, Lawler, Keith V., additional, Levchenko, Sergey V., additional, Lin, Ching Yeh, additional, Liu, Fenglai, additional, Livshits, Ester, additional, Lochan, Rohini C., additional, Luenser, Arne, additional, Manohar, Prashant, additional, Manzer, Samuel F., additional, Mao, Shan-Ping, additional, Mardirossian, Narbe, additional, Marenich, Aleksandr V., additional, Maurer, Simon A., additional, Mayhall, Nicholas J., additional, Neuscamman, Eric, additional, Oana, C. Melania, additional, Olivares-Amaya, Roberto, additional, O’Neill, Darragh P., additional, Parkhill, John A., additional, Perrine, Trilisa M., additional, Peverati, Roberto, additional, Prociuk, Alexander, additional, Rehn, Dirk R., additional, Rosta, Edina, additional, Russ, Nicholas J., additional, Sharada, Shaama M., additional, Sharma, Sandeep, additional, Small, David W., additional, Sodt, Alexander, additional, Stein, Tamar, additional, Stück, David, additional, Su, Yu-Chuan, additional, Thom, Alex J.W., additional, Tsuchimochi, Takashi, additional, Vanovschi, Vitalii, additional, Vogt, Leslie, additional, Vydrov, Oleg, additional, Wang, Tao, additional, Watson, Mark A., additional, Wenzel, Jan, additional, White, Alec, additional, Williams, Christopher F., additional, Yang, Jun, additional, Yeganeh, Sina, additional, Yost, Shane R., additional, You, Zhi-Qiang, additional, Zhang, Igor Ying, additional, Zhang, Xing, additional, Zhao, Yan, additional, Brooks, Bernard R., additional, Chan, Garnet K.L., additional, Chipman, Daniel M., additional, Cramer, Christopher J., additional, Goddard, William A., additional, Gordon, Mark S., additional, Hehre, Warren J., additional, Klamt, Andreas, additional, Schaefer, Henry F., additional, Schmidt, Michael W., additional, Sherrill, C. David, additional, Truhlar, Donald G., additional, Warshel, Arieh, additional, Xu, Xin, additional, Aspuru-Guzik, Alán, additional, Baer, Roi, additional, Bell, Alexis T., additional, Besley, Nicholas A., additional, Chai, Jeng-Da, additional, Dreuw, Andreas, additional, Dunietz, Barry D., additional, Furlani, Thomas R., additional, Gwaltney, Steven R., additional, Hsu, Chao-Ping, additional, Jung, Yousung, additional, Kong, Jing, additional, Lambrecht, Daniel S., additional, Liang, WanZhen, additional, Ochsenfeld, Christian, additional, Rassolov, Vitaly A., additional, Slipchenko, Lyudmila V., additional, Subotnik, Joseph E., additional, Van Voorhis, Troy, additional, Herbert, John M., additional, Krylov, Anna I., additional, Gill, Peter M.W., additional, and Head-Gordon, Martin, additional

Published
2014
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8. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package.

Author

Shao, Yihan, Gan, Zhengting, Epifanovsky, Evgeny, Gilbert, Andrew T.B., Wormit, Michael, Kussmann, Joerg, Lange, Adrian W., Behn, Andrew, Deng, Jia, Feng, Xintian, Ghosh, Debashree, Goldey, Matthew, Horn, Paul R., Jacobson, Leif D., Kaliman, Ilya, Khaliullin, Rustam Z., Kuś, Tomasz, Landau, Arie, Liu, Jie, and Proynov, Emil I.

Subjects
QUANTUM chemistry, DENSITY functional theory, NUCLEAR magnetic resonance spectroscopy, QUANTUM perturbations, CHARGE exchange, GRAPHICAL user interfaces
Abstract

A summary of the technical advances that are incorporated in the fourth major release of theQ-Chemquantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller–Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube. [ABSTRACT FROM AUTHOR]

Published
2015
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9. Advances in methods and algorithms in a modern quantum chemistry program package

Author

Shao, Yihan, primary, Molnar, Laszlo Fusti, additional, Jung, Yousung, additional, Kussmann, Jörg, additional, Ochsenfeld, Christian, additional, Brown, Shawn T., additional, Gilbert, Andrew T.B., additional, Slipchenko, Lyudmila V., additional, Levchenko, Sergey V., additional, O’Neill, Darragh P., additional, DiStasio Jr, Robert A., additional, Lochan, Rohini C., additional, Wang, Tao, additional, Beran, Gregory J.O., additional, Besley, Nicholas A., additional, Herbert, John M., additional, Yeh Lin, Ching, additional, Van Voorhis, Troy, additional, Hung Chien, Siu, additional, Sodt, Alex, additional, Steele, Ryan P., additional, Rassolov, Vitaly A., additional, Maslen, Paul E., additional, Korambath, Prakashan P., additional, Adamson, Ross D., additional, Austin, Brian, additional, Baker, Jon, additional, Byrd, Edward F. C., additional, Dachsel, Holger, additional, Doerksen, Robert J., additional, Dreuw, Andreas, additional, Dunietz, Barry D., additional, Dutoi, Anthony D., additional, Furlani, Thomas R., additional, Gwaltney, Steven R., additional, Heyden, Andreas, additional, Hirata, So, additional, Hsu, Chao-Ping, additional, Kedziora, Gary, additional, Khalliulin, Rustam Z., additional, Klunzinger, Phil, additional, Lee, Aaron M., additional, Lee, Michael S., additional, Liang, WanZhen, additional, Lotan, Itay, additional, Nair, Nikhil, additional, Peters, Baron, additional, Proynov, Emil I., additional, Pieniazek, Piotr A., additional, Min Rhee, Young, additional, Ritchie, Jim, additional, Rosta, Edina, additional, David Sherrill, C., additional, Simmonett, Andrew C., additional, Subotnik, Joseph E., additional, Lee Woodcock III, H., additional, Zhang, Weimin, additional, Bell, Alexis T., additional, Chakraborty, Arup K., additional, Chipman, Daniel M., additional, Keil, Frerich J., additional, Warshel, Arieh, additional, Hehre, Warren J., additional, Schaefer III, Henry F., additional, Kong, Jing, additional, Krylov, Anna I., additional, Gill, Peter M. W., additional, and Head-Gordon, Martin, additional

Published
2006
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10. Effective fragment potential method in Q-CHEM: A guide for users and developers.

Author

Ghosh, Debashree, Kosenkov, Dmytro, Vanovschi, Vitalii, Flick, Joanna, Kaliman, Ilya, Shao, Yihan, Gilbert, Andrew T.B., Krylov, Anna I., and Slipchenko, Lyudmila V.

Subjects
COMPUTATIONAL chemistry, METHODS engineering, QUANTUM mechanics, ELECTRONIC structure, WORK measurement, ELECTRONIC systems
Abstract

A detailed description of the implementation of the effective fragment potential (EFP) method in the Q-CHEM electronic structure package is presented. The Q-CHEM implementation interfaces EFP with standard quantum mechanical (QM) methods such as Hartree-Fock, density functional theory, perturbation theory, and coupled-cluster methods, as well as with methods for electronically excited and open-shell species, for example, configuration interaction, time-dependent density functional theory, and equation-of-motion coupled-cluster models. In addition to the QM/EFP functionality, a 'fragment-only' feature is also available (when the system is described by effective fragments only). To aid further developments of the EFP methodology, a detailed description of the C++ classes and EFP module's workflow is presented. The EFP input structure and EFP job options are described. To assist setting up and performing EFP calculations, a collection of Perl service scripts is provided. The precomputed EFP parameters for standard fragments such as common solvents are stored in Q-CHEM's auxiliary library; they can be easily invoked, similar to specifying standard basis sets. The instructions for generating user-defined EFP parameters are given. Fragments positions can be specified by their center of mass coordinates and Euler angles. The interface with the IQMOL and WEBMO software is also described. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Published
2013
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