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Simulation of (A)over-tilde(1)B(1)->(X)over-tilde(1)A(1) CF2 single vibronic level emissions: Including anharmonic and Duschinsky effects

Simulation of (A)over-tilde(1)B(1)->(X)over-tilde(1)A(1) CF2 single vibronic level emissions: Including anharmonic and Duschinsky effects
Simulation of (A)over-tilde(1)B(1)->(X)over-tilde(1)A(1) CF2 single vibronic level emissions: Including anharmonic and Duschinsky effects
CASSCF/MRCI/aug-cc-pVQZ(no g) and RCCSD(T)/aug-cc-pVQZ potential energy functions were reported for the (A) over tilde B-1(1) and (X) over tilde (1)A(1) states of CF2, respectively. Vibrational wave functions of the symmetric stretching and bending modes of the two states of CF2 were obtained in variational calculations, employing Watson's Hamiltonian for a nonlinear molecule and anharmonic vibrational wave functions expressed as linear combinations of harmonic basis functions. Franck-Condon factors (FCFs) were computed for (A) over tilde B-1(1)-->(X) over tilde (1)A(1) CF2 single vibronic level (SVL) emissions and the SVL emission spectra were simulated with the computed FCFs. When compared with the observed spectra, the simulated spectra obtained in the present investigation, which include allowance for anharmonicity and the Duschinsky effect, were found to be significantly superior to those reported previously, based on the harmonic oscillator model. Using the iterative Franck-Condon analysis procedure, with the geometry of the (X) over tilde (1)A(1) state fixed at the recently determined experimental equilibrium geometry, the geometry of the (A) over tilde B-1(1) state of CF2, which gave the best match between simulated and observed spectra, was found to be r(e)(CF)=1.317 Angstrom and theta (e)(FCF)=121.25 degrees.
least-squares algorithm, difluorocarbene cf2, spectroscopy, photoelectron, halocarbenes, frequencies, molecules, surfaces, system, band
0021-9606
5816-5822
Chau, F. T.
53ebc8f8-5e82-4b34-9795-45f0cb63c4ac
Dyke, J. M.
46393b45-6694-46f3-af20-d7369d26199f
Lee, E. P. F.
f47c6d5d-2d1f-4f03-a3ff-03658812d80b
Mok, D. K. W.
49a4e516-0e71-4f59-a3ec-bd607b47ef33
Chau, F. T.
53ebc8f8-5e82-4b34-9795-45f0cb63c4ac
Dyke, J. M.
46393b45-6694-46f3-af20-d7369d26199f
Lee, E. P. F.
f47c6d5d-2d1f-4f03-a3ff-03658812d80b
Mok, D. K. W.
49a4e516-0e71-4f59-a3ec-bd607b47ef33

Chau, F. T., Dyke, J. M., Lee, E. P. F. and Mok, D. K. W. (2001) Simulation of (A)over-tilde(1)B(1)->(X)over-tilde(1)A(1) CF2 single vibronic level emissions: Including anharmonic and Duschinsky effects. The Journal of Chemical Physics, 115 (13), 5816-5822. (doi:10.1063/1.1398103).

Record type: Article

Abstract

CASSCF/MRCI/aug-cc-pVQZ(no g) and RCCSD(T)/aug-cc-pVQZ potential energy functions were reported for the (A) over tilde B-1(1) and (X) over tilde (1)A(1) states of CF2, respectively. Vibrational wave functions of the symmetric stretching and bending modes of the two states of CF2 were obtained in variational calculations, employing Watson's Hamiltonian for a nonlinear molecule and anharmonic vibrational wave functions expressed as linear combinations of harmonic basis functions. Franck-Condon factors (FCFs) were computed for (A) over tilde B-1(1)-->(X) over tilde (1)A(1) CF2 single vibronic level (SVL) emissions and the SVL emission spectra were simulated with the computed FCFs. When compared with the observed spectra, the simulated spectra obtained in the present investigation, which include allowance for anharmonicity and the Duschinsky effect, were found to be significantly superior to those reported previously, based on the harmonic oscillator model. Using the iterative Franck-Condon analysis procedure, with the geometry of the (X) over tilde (1)A(1) state fixed at the recently determined experimental equilibrium geometry, the geometry of the (A) over tilde B-1(1) state of CF2, which gave the best match between simulated and observed spectra, was found to be r(e)(CF)=1.317 Angstrom and theta (e)(FCF)=121.25 degrees.

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Published date: 1 October 2001
Keywords: least-squares algorithm, difluorocarbene cf2, spectroscopy, photoelectron, halocarbenes, frequencies, molecules, surfaces, system, band

Identifiers

Local EPrints ID: 19448
URI: http://eprints.soton.ac.uk/id/eprint/19448
ISSN: 0021-9606
PURE UUID: 260e79df-1d88-4c94-ba60-d54f512edcb4
ORCID for J. M. Dyke: ORCID iD orcid.org/0000-0002-9808-303X

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Date deposited: 14 Feb 2006
Last modified: 16 Mar 2024 02:36

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Contributors

Author: F. T. Chau
Author: J. M. Dyke ORCID iD
Author: E. P. F. Lee
Author: D. K. W. Mok

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