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Updated: Jul 19, 2026

ARL Spectral Fitting as an Application to Augment Spectral Data via Franck-Condon Lineshape Analysis and Color Analysis
Published on: August 19, 2021
A variational approach for calculating Franck-Condon factors including mode-mode anharmonic coupling
Josep M Luis1, Bernard Kirtman, Ove Christiansen
1Institute of Computational Chemistry, University of Girona, Campus de Montilivi, Girona, 17071 Catalonia, Spain. josepm.luis@udg.es
Abstract:
We have implemented our new procedure for computing Franck-Condon factors utilizing vibrational configuration interaction based on a vibrational self-consistent field reference. Both Duschinsky rotations and anharmonic three-mode coupling are taken into account. Simulations of the first ionization band of ClO(2) and C(4)H(4)O (furan) using up to quadruple excitations in treating anharmonicity are reported and analyzed. A developer version of the MIDASCPP code was employed to obtain the required anharmonic vibrational integrals and transition frequencies.
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