An accurate semi-empirical potential model for the a  3Σu+ state of the alkali dimers Na2, K2, Rb2, and Cs2 which reproduces the scattering length

Abstract

A new four parameter Tang-Toennies type potential model is described for the a 3Σu+ triplet state of the alkali dimers Na2, K2, Rb2, and Cs2. Compared to an earlier three parameter semi-empirical model based on the experimental well depth, De, well location, Re, and the harmonic vibrational frequency, ωe [Lau et al., J. Chem. Phys. 145, 194308 (2016)], the new model is also adjusted to be consistent with the scattering length. The results are shown to have a similar good agreement with the spectroscopic term values as the earlier model with the advantage that the scattering length is properly described. The deviations from recent potentials for Cs2 are discussed.

An accurate potential model for the a3Σu+ state of the lithium dimer

“…This is to be compared with the experimental value of − 27.3 ± 0.8 a.u. 6 In recent years, many scattering lengths reported in literature 21,78–80 were calculated with a semiclassical formula, developed by Gribakin and Flambaum 81 with n = 6 and γ = (2 μC 6 ) 1/2 / ħ ( ħ = 1 in the atomic unit). R 0 is defined by V ( R 0 ) = 0.…”

“…This is to be compared with the experimental value of À 27.3 AE 0.8 a.u. 6 In recent years, many scattering lengths reported in literature 21,[78][79][80] were calculated with a semiclassical formula, developed by Gribakin and Flambaum 81…”

“…Later this potential was further improved with an additional parameter d in the repulsion Ae ÀbRÀcR 2 ÀdR 3 so that the scattering length could also be reproduced. 21 These parameters are fit by numerically solving nonlinear differential equations. The improved models provide a good description of the a 3 S u + state potentials for Na 2 , K 2 , Rb 2 and Cs 2 , but not for Li 2 .…”

Ab initio calculation of the spectrum of Feshbach resonances in NaLi + Na collisions

“…The repulsive part of the two-body potential is less accurate than its long-range part. This introduces additional uncertainty to the overall potential, which can be as high as 16 cm −1 (an additional uncertainty of ∼3 cm −1 of the three-body interaction), estimated from the difference between an experimental two-body potential for Na 2 [60] and a highly accurate theoretical potential for NaLi [15].…”

Rovibrationally resolved radiative lifetime and collisional cross section measurements of the 61Σg+(v=6,Wagle1, Pant2, Converse3 et al. 2021Journal of Quantitative Spectroscopy and Radiative Transfer0000View full textAdd to dashboardCite

“…Since the separation between the vibrational and rotational quantum levels of the sodium dimer are approximately 150 cm -1 and 10 cm -1 (1 cm -1 ≈ 30 GHz) respectively, the pulsed dye lasers are suitable for optical transitions. The study of potential energy curves for the ground and excited states of alkali molecule has always been the matter of interest in atomic, molecular and optical physics area [9,10]. The 6 1 Σ + g (3s+5s) state of Na 2 is of special importance because of the presence of a double well [11], with the secondary well locating at large internuclear distance, as shown in Fig.…”