Ab initio calculations on SF2 and its low-lying cationic states: Anharmonic Franck-Condon simulation of the uv photoelectron spectrum of SF2

Ab initio calculations on SF2 and its low-lying cationic states: Anharmonic Franck-Condon simulation of the uv photoelectron spectrum of SF2

Geometry optimization calculations were carried out on the X (1)A(1) state of SF2 and the X B-2(1), A (2)A(1), B B-2(2), C B-2(2), D (2)A(1), and E (2)A(2) states of SF2+ employing the restricted-spin coupled-cluster single-double plus perturbative triple excitation [RCCSD(T)] method and basis sets of up to the augmented correlation-consistent polarized quintuple-zeta [aug-cc-pV(5+d)Z] quality. Effects of core electron (S 2s(2)2p(6) and F 1s(2) electrons) correlation and basis set extension to the complete basis set limit on the computed minimum-energy geometries and relative electronic energies (adiabatic and vertical ionization energies) were investigated. RCCSD(T) potential energy functions (PEFs) were calculated for the X (1)A(1) state of SF2 and the low-lying states of SF2+ listed above employing the aug-cc-pV(5+d)Z and aug-cc-pV5Z basis sets for S and F, respectively. Anharmonic vibrational wave functions of these neutral and cationic states of SF2, and Franck-Condon (FC) factors of the lowest four one-electron allowed neutral photoionizations were computed employing the RCCSD(T) PEFs. Calculated FC factors with allowance for Duschinsky rotation and anharmonicity were used to simulate the first four photoelectron bands of SF2. The agreement between the simulated and observed first bands in the He I photoelectron spectrum reported by de Leeuw [Chem. Phys. 34, 287 (1978)] is excellent. Our calculations largely support assignments made by de Leeuw on the higher ionization energy bands of SF2.

enhanced multiphoton ionization, excited electronic states, lower
chalcogen fluorides, sulfur difluoride, microwave-spectrum, infrared-spectrum, emission-spectrum, basis-sets, thermochemistry, energies

104304-[13pp]

Lee, Edmond P.F.

f47c6d5d-2d1f-4f03-a3ff-03658812d80b

Mok, Daniel K.W.

49a4e516-0e71-4f59-a3ec-bd607b47ef33

Chau, Foo-tim

e15ec394-d11b-4cbe-91f3-cdac037d9d0e

Dyke, John M.

46393b45-6694-46f3-af20-d7369d26199f

September 2006

Lee, Edmond P.F.

f47c6d5d-2d1f-4f03-a3ff-03658812d80b

Mok, Daniel K.W.

49a4e516-0e71-4f59-a3ec-bd607b47ef33

Chau, Foo-tim

e15ec394-d11b-4cbe-91f3-cdac037d9d0e

Dyke, John M.

46393b45-6694-46f3-af20-d7369d26199f

Lee, Edmond P.F., Mok, Daniel K.W., Chau, Foo-tim and Dyke, John M.
(2006)
Ab initio calculations on SF2 and its low-lying cationic states: Anharmonic Franck-Condon simulation of the uv photoelectron spectrum of SF2.
*The Journal of Chemical Physics*, 125 (10), .
(doi:10.1063/1.2227380).
(PMID:1699952)

## Abstract

Geometry optimization calculations were carried out on the X (1)A(1) state of SF2 and the X B-2(1), A (2)A(1), B B-2(2), C B-2(2), D (2)A(1), and E (2)A(2) states of SF2+ employing the restricted-spin coupled-cluster single-double plus perturbative triple excitation [RCCSD(T)] method and basis sets of up to the augmented correlation-consistent polarized quintuple-zeta [aug-cc-pV(5+d)Z] quality. Effects of core electron (S 2s(2)2p(6) and F 1s(2) electrons) correlation and basis set extension to the complete basis set limit on the computed minimum-energy geometries and relative electronic energies (adiabatic and vertical ionization energies) were investigated. RCCSD(T) potential energy functions (PEFs) were calculated for the X (1)A(1) state of SF2 and the low-lying states of SF2+ listed above employing the aug-cc-pV(5+d)Z and aug-cc-pV5Z basis sets for S and F, respectively. Anharmonic vibrational wave functions of these neutral and cationic states of SF2, and Franck-Condon (FC) factors of the lowest four one-electron allowed neutral photoionizations were computed employing the RCCSD(T) PEFs. Calculated FC factors with allowance for Duschinsky rotation and anharmonicity were used to simulate the first four photoelectron bands of SF2. The agreement between the simulated and observed first bands in the He I photoelectron spectrum reported by de Leeuw [Chem. Phys. 34, 287 (1978)] is excellent. Our calculations largely support assignments made by de Leeuw on the higher ionization energy bands of SF2.

Text

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## More information

Published date: September 2006

Keywords:
enhanced multiphoton ionization, excited electronic states, lower
chalcogen fluorides, sulfur difluoride, microwave-spectrum, infrared-spectrum, emission-spectrum, basis-sets, thermochemistry, energies

Organisations:
Chemistry

## Identifiers

Local EPrints ID: 174183

URI: http://eprints.soton.ac.uk/id/eprint/174183

ISSN: 0021-9606

PURE UUID: c1fff8df-062d-4759-bbf2-91cc8c222a67

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Date deposited: 11 Feb 2011 13:53

Last modified: 20 Jul 2019 01:27

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## Contributors

Author:
Edmond P.F. Lee

Author:
Daniel K.W. Mok

Author:
Foo-tim Chau

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