Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/5051
Title: Ab initio calculations on the X˜²B₁and òA₁states of AsH₂, and Franck--Condon simulation, including anharmonicity, of the Ã(0,0,0)-X˜ single vibronic level emission spectrum of AsH₂
Authors: Lee, Edmond P. F.
Mok, Daniel K. W.
Chau, Foo-tim
Dyke, John M.
Subjects: Ab initio calculations
Arsenic compounds
Coupled cluster calculations
Fluorescence
Franck-Condon factors
Perturbation theory
Potential energy functions
Variational techniques
Vibrational states
Issue Date: 21-Jun-2010
Publisher: American Institute of Physics
Source: Journal of chemical physics, 21 June 2010, v. 132, no. 23, 234309, p. 1-12.
Abstract: Restricted-spin coupled-cluster single-double plus perturbative triple excitation {RCCSD(T)} calculations were carried out on the X˜²B₁and òA₁states of AsH₂employing the fully relativistic small-core effective core potential (ECP10MDF) for As and basis sets of up to the augmented correlation-consistent polarized valence quintuple-zeta (aug-cc-pV5Z) quality. Minimum-energy geometrical parameters and relative electronic energies were evaluated, including contributions from extrapolation to the complete basis set limit and from outer core correlation of the As 3d¹⁰ electrons employing additional tight 4d3f2g2h functions designed for As. In addition, simplified, explicitly correlated CCSD(T)-F12 calculations were also performed employing different atomic orbital basis sets of up to aug-cc-pVQZ quality, and associated complementary auxiliary and density-fitting basis sets. The best theoretical estimate of the relative electronic energy of the òA₁state of AsH₂ relative to the X˜²B₁state including zero-point energy correction (T₀) is 19 954(32) cm⁻¹, which agrees very well with available experimental T₀ values of 19 909.4531(18) and 19 909.4910(17) cm⁻¹ obtained from recent laser induced fluorescence and cavity ringdown absorption spectroscopic studies. In addition, potential energy functions (PEFs) of the X˜²B₁and òA₁states of AsH₂ were computed at different RCCSD(T) and CCSD(T)-F12 levels. These PEFs were used in variational calculations of anharmonic vibrational wave functions, which were then utilized to calculate Franck–Condon factors (FCFs) between these two states, using a method which includes allowance for anharmonicity and Duschinsky rotation. The à (0,0,0)-X˜ single vibronic level (SVL)emission spectrum of AsH₂was simulated using these computed FCFs. Comparison between simulated and available experimental vibrationally resolved spectra of the à (0,0,0)-X˜ (SVL) emission of AsH₂, which consist essentially of the bending (2[sub n]) series, suggests that there is a significant loss in intensity in the low emission energy region of the experimental spectrum.
Rights: © 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in E. P. F. Lee et al., J. Chem. Phys. 132, 234309 (2010) and may be found at http://link.aip.org/link/?jcp/132/234309.
Type: Journal/Magazine Article
URI: http://hdl.handle.net/10397/5051
DOI: 10.1063/1.3442748
ISSN: 1089-7690 (online)
0021-9606 (print)
Appears in Collections:ABCT Journal/Magazine Articles

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