Results 321 to 330 of about 1,610,034 (354)

MP2, DFT and ab initio calculations on thioxanthone

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011
Density functional theory (DFT), HF and MP2 calculations have been carried out to investigate thioxanthone molecule using the standard 6-31+G(d,p) basis set. The results of MP2 calculations show a butterfly structure for thioxanthone. The calculated results show that the predicted geometry can well reproduce the structural parameters.
Alireza Salimi, Beni, Alireza Najafi, Chermahini, Hashem, Sharghi, Setareh Mirzaei, Monfared   +3 more
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Ab initio Calculations of Phonon Dispersion in CdGa2S4

Physics of the Solid State, 2017
Abstract—The phonon spectrum of CdGa2S4 has been experimentally investigated by Raman spectroscopy and theoretically analyzed using the density functional theory (DFT). Eleven active Raman modes (at 83, 135, 165, 219, 243, 260, 310, 322, 352, 361, and 392 cm–1) have been detected and identified.
Z. A. Dzhakhangirli, T. G. Kerimova, N. A. Abdullayev, I. A. Mamedova, N. T. Mamedov   +4 more
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Ab Initio Calculations on the Formation and Rearrangement of Spiropentane

The Journal of Physical Chemistry A, 2009
The formation of spiropentane, by addition of singlet (1A1) methylene to methylenecyclopropane, and the unimolecular reactions of spiropentane have all been studied computationally. Benchmark calculations on two key biradicals were conducted by the multireference Mukherjee's coupled-cluster (MkCC) method.
Barry K, Carpenter, Jiri, Pittner, Libor, Veis   +2 more
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Ab-Initio Calculations of the Vibrational Properties of Nanostructures

2012
We study, via ab initio density functional theory (DFT), the vibrational properties of semiconductor colloidal nanostructures. The calculations are performed on the NEC Nehalem clusters at the High Performance Computing Center Stuttgart (HLRS). We find a relatively large blue shift of the longitudinal acoustic, transverse and longitudinal optical modes
Gabriel Bester, Peng Han
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Ab Initio Calculations of Clusters

2004
Both ab initio quantum chemistry and the investigation of atomic or molecular clusters are fields of active research nowadays. This contribution presents on one hand some advances in making programs efficient for calculations of large systems, on the other it shows some fruitful combinations of calculated and experimental results.
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Geometry optimization in ab initio SCF calculations

Journal of Molecular Structure: THEOCHEM, 1980
Abstract The floating orbital geometry optimization (FOGO) described previously is applied to H2O2, NH3, HNC, HNO, HNCO, and CH3OH. In the FOGO method we apply two analytically calculated energy gradients in a variable metric method. Some orbitals are no longer fixed on the corresponding nuclei, but their position is optimized simultaneously with the
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Ab-initio ZORA calculations

2000
In this paper we present the first application of the ZORA (Zeroth Order Regular Approximation of the Dirac Fock equation) formalism in Ab Initio electronic structure calculations. The ZORA method, which has been tested previously in the context of Density Functional Theory, has been implemented in the GAMESS-UK package.
Faas, S., Snijders, Jaap, van Lenthe, J.H.   +2 more
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Ab initio calculations on a microcomputer

Journal of Chemical Education, 1987
Lynne H. Reed, Arthur R. Murphy
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Ab Initio Calculations

1980
Petr Čársky, Miroslav Urban
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Ab initio calculation of anharmonic vibrational states of polyatomic systems: Electronic structure combined with vibrational self-consistent field

Journal of Chemical Physics, 1999
Robert Benny Gerber, Galina M Chaban
exaly