Global analysis of data on the spin-orbit-coupledA1Σu+and

Jianmei Bai

¹

,

Ergin Ahmed

²

,

Bediha Beser

³

et al.

Abstract

We present experimentally derived potential curves and spin-orbit interaction functions for the strongly perturbed A 1 Σ + u and b 3 Πu states of the cesium dimer. The results are based on data from several sources. Laser-induced fluorescence Fourier transform spectroscopy (LIF FTS) was used some time ago in the Laboratoire Aimé Cotton primarily to study the X 1 Σ + g state. More recent work at Tsinghua University provides information from moderate resolution spectroscopy on the lowest levels of the b 3 Π ± 0u states as well as additional high resolution data. From Innsbruck University, we have precision data obtained with cold Cs2 molecules. Recent data from Temple University was obtained using the optical-optical double resonance polarization spectroscopy technique, and finally, a group at the University of Latvia has added additional LIF FTS data. In the Hamiltonian matrix, we have used analytic potentials (the Expanded Morse Oscillator form) with both finite-difference (FD) coupled-channels and discrete variable representation (DVR) calculations of the term values. Fitted diagonal and off-diagonal spin-orbit functions are obtained and compared with ab initio results from Temple and Moscow State universities.

Theoretical study of spin–orbit and Coriolis coupling among the low-lying states of Rb2 and Cs2

“…We believe that the accuracy of the present SOC matrix elements is higher the previous all-electrons non-relativistic [16] and relativistic [8,20,22] structure calculations. The present SOC results seem to be slightly better or comparable with the most recent ECP-MRCI studies [18,19] of Rb 2 whereas the present SOC results of Cs 2 should be more reliable than the large core (1 electron) pseudopotential calculations [13,14].…”

“…The relevant empirical functions are borrowed from Refs. [21,22]. Figure 2: The spin-orbit functions of Rb 2 calculated between the several states of usymmetry (a) and all states of g-symmetry (b) converging to the second 5 2 S+5 2 P dissociation limit.…”

“…The present results also validate angular coupling contribution into adiabatic correction of the A 1 Σ + u and b 3 Π u states which was approximately treated in Refs. [20,21,22] as [l(l + 1) − Λ 2 ]/2µR 2 with l = 1 and Λ = 0, 1.…”

“…Figure 1: The off-diagonal (a) and diagonal (b) spin-orbit matrix elements of the A 1 Σ + u ∼b 3 Π u complex of Rb 2 and Cs 2 . The PW -present work, ab1 -the relativistic MR-RAS-CI results [20,22], ab2 -effective core potential MRCI studies [18,19], ab3 -all-electrons MRD-CI calculation [16]. The relevant empirical functions are borrowed from Refs.…”

“…[18,19] due to all electrons multi-reference configuration interaction (MRCI) calculations. There are also relativistic MR-RAS-CI calculations of the SO functions for the lowest excited A 1 Σ + u and b 3 Π u states devoted to CC deperturbation analysis of the singlet-triplet A − b complex of the both Rb 2 [20,21] and Cs 2 molecules [22]. A comprehensive set of the SO matrix elements of Cs 2 (except the high quality Spies's PhD thesis [14] published in 1989 and the second order SO splitting of the a 3 Σ + u potential presented in Refs [8,15]) is not available in explicit form yet.…”