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Title: Fourier-transform spectroscopy and coupled-channels deperturbation treatment of the A {sup 1{Sigma}+}-b {sup 3{Pi}} complex of KCs

Journal Article · · Physical Review. A
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  1. Laser Center, University of Latvia, Rainis Boulevard 19, LV-1586 Riga (Latvia)

The laser-induced fluorescence (LIF) A {sup 1{Sigma}+}-b {sup 3{Pi}{yields}}X {sup 1{Sigma}+} spectra of the KCs molecule were recorded in a near infrared region by a Fourier-transform spectrometer with a resolution of 0.03 cm{sup -1}. Overall more than 200 collisionally enhanced LIF spectra were rotationally assigned to {sup 39}K{sup 133}Cs and {sup 41}K{sup 133}Cs isotopomers yielding more than 3400 rovibronic term values of the strongly mixed singlet A {sup 1{Sigma}+} and triplet b {sup 3{Pi}} states with the uncertainty of 0.003-0.01 cm{sup -1}. Experimental data massive starts from the lowest vibrational level v{sub A}=0 of the singlet and nonuniformly covers the energy range E is an element of [10 040,13 250] cm{sup -1} with rotational quantum numbers J{sup '} is an element of [7,225]. Besides the dominating regular A {sup 1{Sigma}+}-b {sup 3{Pi}}{sub {Omega}=0} interactions, the weak local heterogeneous A {sup 1{Sigma}+}-b {sup 3{Pi}}{sub {Omega}=1} perturbations have been discovered and analyzed. Coupled-channels deperturbation analysis of the experimental {sup 39}K{sup 133}Cs e-parity term values of the A {sup 1{Sigma}+}-b {sup 3{Pi}}{sub {Omega}=0,1,2} complex was accomplished in the framework of the phenomenological 4x4 Hamiltonian accounting implicitly for regular interactions with the remote {sup 1{Pi}} and {sup 3{Sigma}+} states. The diabatic potential energy curves of the A {sup 1{Sigma}+} and b {sup 3{Pi}} states, as well as relevant spin-orbit coupling matrix elements, were defined analytically with the expanded Morse oscillators model. The obtained parameters reproduce 95% of experimental data field of the {sup 39}K{sup 133}Cs isotopomer with a standard deviation of 0.004 cm{sup -1}, which is consistent with the uncertainty of the experiment. Reliability of the derived parameters was confirmed by a good agreement between the predicted and experimental term values of the {sup 41}K{sup 133}Cs isotopomer. The calculated relative intensity distributions in A-b{yields}X LIF progressions are also consistent with their experimental counterparts. The deperturbation model was applied for simulation of a pump-dump optical cycle a {sup 3{Sigma}+{yields}}A {sup 1{Sigma}+}-b {sup 3{Pi}{yields}}X {sup 1{Sigma}+} proposed for transformation of ultracold KCs molecules to their absolute ground state v{sub X}=0;J{sub X}=0.

OSTI ID:
21408598
Journal Information:
Physical Review. A, Vol. 81, Issue 4; Other Information: DOI: 10.1103/PhysRevA.81.042509; (c) 2010 The American Physical Society; ISSN 1050-2947
Country of Publication:
United States
Language:
English