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The singlet-triplet separation in CF2: state-of-the-art ab initio calculations and Franck-Condon simulations including anharmonicity

The singlet-triplet separation in CF2: state-of-the-art ab initio calculations and Franck-Condon simulations including anharmonicity
The singlet-triplet separation in CF2: state-of-the-art ab initio calculations and Franck-Condon simulations including anharmonicity
Geometrical parameters, vibrational frequencies and relative electronic energies of the X(2)B(1) state of CF(2) (-) and the X(1)A(1) and a(3)B(1) states of CF(2) have been calculated. Core-electron effects on the computed minimum-energy geometries and relative electronic energies have been investigated, and relativistic contributions to the computed relative electronic energies calculated. Potential energy functions of the X(2)B(1) state of CF(2) (-) and the X(1)A(1) and a(3)B(1) states of CF(2) have been determined, and anharmonic vibrational wavefunctions of these states calculated variationally. Franck-Condon factors including anharmonicity and Duschinsky rotation have been computed and used to simulate the a-X emission spectrum of CF(2) determined by S. Koda [Chem. Phys. Lett. 1978, 55, 353] and the 364 nm laser photodetachment spectrum of CF(2) (-) obtained by R. L. Schwartz et al. [J. Phys. Chem. A 1999, 103, 8213]. Comparison between theory and experiment shows that the theoretical approach benchmarked in the present study is able to give highly reliable positions for the CF(2)(X(1)A(1))+e?CF(2) (-)(X(2)B(1)) and CF(2)(a(3)B(1))+e?CF(2) (-)(X(2)B(1)) bands in the photoelectron spectrum of CF(2) (-) and a reliable singlet-triplet gap for CF(2). It is therefore concluded that the same theoretical approach should give reliable simulated CCl(2)(X(1)A(1))+e?CCl(2) (-)(X(2)B(1)) and CCl(2)(a(3)B(1))+e?CCl(2) (-)(X(2)B(1)) bands in the photodetachment spectrum of CCl(2) (-) and a reliable singlet-triplet gap for CCl(2).
ab initio calculations, franck-condon factors, photochemistry, photoelectron spectroscopy, spectral simulations, correlated molecular calculations, ion photoelectron-spectroscopy, halocarbene anions hcf, gaussian-basis sets, ccl2, difluorocarbene, methylene, constants, spectra, atoms
1439-4235
2037-2045
Chau, Foo-tim
e15ec394-d11b-4cbe-91f3-cdac037d9d0e
Mok, Daniel K.W.
49a4e516-0e71-4f59-a3ec-bd607b47ef33
Lee, Edmond P.F.
f47c6d5d-2d1f-4f03-a3ff-03658812d80b
Dyke, John M.
46393b45-6694-46f3-af20-d7369d26199f
Chau, Foo-tim
e15ec394-d11b-4cbe-91f3-cdac037d9d0e
Mok, Daniel K.W.
49a4e516-0e71-4f59-a3ec-bd607b47ef33
Lee, Edmond P.F.
f47c6d5d-2d1f-4f03-a3ff-03658812d80b
Dyke, John M.
46393b45-6694-46f3-af20-d7369d26199f

Chau, Foo-tim, Mok, Daniel K.W., Lee, Edmond P.F. and Dyke, John M. (2005) The singlet-triplet separation in CF2: state-of-the-art ab initio calculations and Franck-Condon simulations including anharmonicity. ChemPhysChem, 6 (10), 2037-2045. (doi:10.1002/cphc.200500114).

Record type: Article

Abstract

Geometrical parameters, vibrational frequencies and relative electronic energies of the X(2)B(1) state of CF(2) (-) and the X(1)A(1) and a(3)B(1) states of CF(2) have been calculated. Core-electron effects on the computed minimum-energy geometries and relative electronic energies have been investigated, and relativistic contributions to the computed relative electronic energies calculated. Potential energy functions of the X(2)B(1) state of CF(2) (-) and the X(1)A(1) and a(3)B(1) states of CF(2) have been determined, and anharmonic vibrational wavefunctions of these states calculated variationally. Franck-Condon factors including anharmonicity and Duschinsky rotation have been computed and used to simulate the a-X emission spectrum of CF(2) determined by S. Koda [Chem. Phys. Lett. 1978, 55, 353] and the 364 nm laser photodetachment spectrum of CF(2) (-) obtained by R. L. Schwartz et al. [J. Phys. Chem. A 1999, 103, 8213]. Comparison between theory and experiment shows that the theoretical approach benchmarked in the present study is able to give highly reliable positions for the CF(2)(X(1)A(1))+e?CF(2) (-)(X(2)B(1)) and CF(2)(a(3)B(1))+e?CF(2) (-)(X(2)B(1)) bands in the photoelectron spectrum of CF(2) (-) and a reliable singlet-triplet gap for CF(2). It is therefore concluded that the same theoretical approach should give reliable simulated CCl(2)(X(1)A(1))+e?CCl(2) (-)(X(2)B(1)) and CCl(2)(a(3)B(1))+e?CCl(2) (-)(X(2)B(1)) bands in the photodetachment spectrum of CCl(2) (-) and a reliable singlet-triplet gap for CCl(2).

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Published date: 14 October 2005
Keywords: ab initio calculations, franck-condon factors, photochemistry, photoelectron spectroscopy, spectral simulations, correlated molecular calculations, ion photoelectron-spectroscopy, halocarbene anions hcf, gaussian-basis sets, ccl2, difluorocarbene, methylene, constants, spectra, atoms

Identifiers

Local EPrints ID: 20757
URI: http://eprints.soton.ac.uk/id/eprint/20757
ISSN: 1439-4235
PURE UUID: 9ab4eb70-67be-4c5c-91fa-367a219b003d
ORCID for John M. Dyke: ORCID iD orcid.org/0000-0002-9808-303X

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Date deposited: 02 Mar 2006
Last modified: 10 Dec 2019 01:59

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Contributors

Author: Foo-tim Chau
Author: Daniel K.W. Mok
Author: Edmond P.F. Lee
Author: John M. Dyke ORCID iD

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