Experimental study of the Ca $\mathsf{_2}$ $\mathsf{^1}$ S $\mathsf{+^1}$ S asymptote

Abstract

The filtered laser excitation technique was applied for measuring transition frequencies of the Ca2 B-X system from asymptotic levels of the X 1 Σ + g ground state reaching v ′′ = 38. That level has an outer classical turning point of about 20Å which is only 0.2 cm −1 below the molecular 1 S+ 1 S asymptote. Extensive analysis of the spectroscopic data, involving Monte Carlo simulation, allowed for a purely experimental determination of the long range parameters of the potential energy curve.The possible values of the s-wave scattering length could be limited to be between 250a0 and 1000a0.

Theoretical predictions of properties of group-2 elements including element 120 and their adsorption on noble metal surfaces

“…The homonuclear dimers, M 2 , of Ca through Ra were a subject of experimental [16][17][18] and theoretical [19][20][21][22][23][24][25] studies in the past because of their weakly bound ground states at large interatomic distances. There are, to our knowledge, fewer data on MAu: only experimental [26][27][28] and theoretical 26 on CaAu, and theoretical 29 on BaAu.…”

Scattering lengths of calcium and barium isotopes

“…With the exception of systems with only a few electrons, like metastable helium [22], ab initio potentials are in general not accurate enough and constraints from experimental data are required. For Ca 2 , an analytic representation of the X 1 + g potential based on an extensive set of experimental data from the Tiemann group is available [23]. For Ba 2 , [24].…”

“…Information on the Ca 2 X 1 + g potential has been gathered by several spectroscopic methods, including photoassociation spectroscopy [26][27][28], Fourier-transform spectroscopy [29], and filtered laser excitation technique [23]. Based on these detailed spectroscopic data, an interval of the scattering length for 40 Ca is determined to be 340-700 a 0 [28].…”

“…1). We allow the C 6 long-range coefficient to vary within a factor 0.991 to 1.003 from its reported value [23], in order to reproduce the scattering length interval for 40 Ca. We then take the mass as a variable parameter and calculate the scattering length for the full mass interval spanned by the stable even isotopes.…”

Atomic C 6 dispersion coefficients: a four-component relativistic Kohn–Sham study

“…In Table 1 we have also compiled a selection of literature values. We have only been able to find a very limited set of C 6 values derived from experiment [47][48][49]55,65]. Most literature values listed have therefore been calculated by a variety of methods, including DFT [45,67], manybody perturbation theory [44,52,58,61,62], Coupled Cluster(CC) [46,51,56,59,63,64,66] and Configuration Interaction (CI) [43].…”