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Calculation of Franck-Condon factors including anharmonicity: simulation of the C2 H4+ X̃2B 3u←C2 H4X̃1 Ag band in the photoelectron spectrum of ethylene

Our new simple method for calculating accurate Franck-Condon factors including nondiagonal (i.e., mode-mode) anharmonic coupling is used to simulate the C2H4+X2B 3u←C2H4X̃1 Ag band in the photoelectron spectrum. An improved vibrational basis set truncation algorithm, which permits very efficient computations, is employed. Because the torsional mode is highly anharmonic it is separated from the other modes and treated exactly. All other modes are treated through the second-order perturbation theory. The perturbation-theory corrections are significant and lead to a good agreement with experiment, although the separability assumption for torsion causes the C2 D4 results to be not as good as those for C2 H4. A variational formulation to overcome this circumstance, and deal with large anharmonicities in general, is suggested

© Journal of Chemical Physics, 2005, vol. 122, núm. 18

American Institute of Physics

Author: Luis Luis, Josep Maria
Torrent Sucarrat, Miquel
Solà i Puig, Miquel
Bishop, David M.
Kirtman, Bernard
Date: 2005
Abstract: Our new simple method for calculating accurate Franck-Condon factors including nondiagonal (i.e., mode-mode) anharmonic coupling is used to simulate the C2H4+X2B 3u←C2H4X̃1 Ag band in the photoelectron spectrum. An improved vibrational basis set truncation algorithm, which permits very efficient computations, is employed. Because the torsional mode is highly anharmonic it is separated from the other modes and treated exactly. All other modes are treated through the second-order perturbation theory. The perturbation-theory corrections are significant and lead to a good agreement with experiment, although the separability assumption for torsion causes the C2 D4 results to be not as good as those for C2 H4. A variational formulation to overcome this circumstance, and deal with large anharmonicities in general, is suggested
Format: application/pdf
Citation: Luis, J.M., Torrent-Sucarrat, M., Solà, M., Bishop, D.M., i Kirtman, B. (2005). Calculation of Franck-Condon factors including anharmonicity: simulation of the C2 H4 + X̃2B 3u←C2 H4X̃1 Ag band in the photoelectron spectrum of ethylene. Journal of Chemical Physics, 122 (18), 184104. Recuperat 24 març 2011, a http://link.aip.org/link/doi/10.1063/1.1896362
ISSN: 0021-9606 (versió paper)
1089-7690 (versió electrònica)
Document access: http://hdl.handle.net/10256/3277
Language: eng
Publisher: American Institute of Physics
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.1063/1.1896362
Articles publicats (D-Q)
Is part of: © Journal of Chemical Physics, 2005, vol. 122, núm. 18
Rights: Tots els drets reservats
Subject: Algorismes
Anàlisi espectral
Anàlisi harmònica
Dinàmica molecular -- Simulació per ordinador
Espectroscòpia fotoelèctrica
Etilè
Pertorbació (Matemàtica)
Polarització (Electricitat)
Algorithms
Ethylene
Harmonic analysis
Molecular dynamics -- Computer simulation
Perturbation (Mathematics)
Photoelectron spectroscopy
Polarization (Electricity)
Spectrum analysis
Title: Calculation of Franck-Condon factors including anharmonicity: simulation of the C2 H4+ X̃2B 3u←C2 H4X̃1 Ag band in the photoelectron spectrum of ethylene
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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