Effects of anisotropic interaction-induced properties of hydrogen-rare gas compounds on rototranslational Raman scattering spectra: Comprehensive theoretical and numerical analysis

Abstract

A comprehensive study is presented of many aspects of the depolarized anisotropic collision induced (CI) component of light scattered by weakly bound compounds composed of a dihydrogen molecule and a rare gas (Rg) atom, H2-Rg. The work continues a series of earlier projects marking the revival of interest in linear light scattering following the development of new highly advanced tools of quantum chemistry and other theoretical, computational, and experimental means of spectral analyses. Sophisticated ab initio computing procedures are applied in order to obtain the anisotropic polarizability component's dependence on the H2-Rg geometry. These data are then used to evaluate the CI spectral lines for all types of Rg atoms ranging from He to Xe (Rn excluded). Evolution of the properties of CI spectra with growing polarizability/masses of the complexes studied is observed. Special attention is given to the heaviest, Kr and Xe based, scatterers. The influence of specific factors shaping the spectral lines (e.g., bound and metastable contribution, potential anisotropy) is discussed. Also the share of pressure broadened allowed rotational transitions in the overall spectral profile is taken into account and the extent to which it is separable from the pure CI contribution is discussed. We finish with a brief comparison between the obtained results and available experimental data.

Dirac bubble potential for He–He and inadequacies in the continuum: Comparing an analytic model with elastic collision experiments

“…50), in the case of the EDbp (r c 0), λ satisfies the more general expression of Eqs. (14) and (15), which is neither monotonous nor continuous at x = κr c .…”

“…However, by plugging κ = 0.005 520 bohr 1 and r 0 = 13.15 bohr into Eqs. (14) and (15), new values for λ 4-4 are obtained depending on the choice of r c , instead of the previous λ 4-4 = − 1.0741 (the value of κ is from data for the 4 He- 4 He binding energy; the value of r 0 stems from maximization of the overlap between the bound-state wavefunction of 4 He 2 in the Dbp model and an ab initio computation). For instance, with r c = 3.2 bohr, viz., two atoms with interpenetrating van der Waals halos (see footnote Ref.…”

“…Quantum chemistry offers unrivalled resources to suit the needs of physicists for reliable models to address pairwise interactions and electric properties relevant to weakly interconnected light atomic "clusters": interaction potential, [1][2][3][4][5][6][7][8] dipole polarizability, [9][10][11][12][13][14][15][16][17][18] hyperpolarizabilities, [16][17][18][19] and dipole moment. 8,13,17,[20][21][22] The smallest "unit" of such clusters is collisional atomic pairs, their prototype being 4 He- 4 He and the related isotopologues 3 He- 3 He and 3 He- 4 He.…”

“…8,13,17,[20][21][22] The smallest "unit" of such clusters is collisional atomic pairs, their prototype being 4 He- 4 He and the related isotopologues 3 He- 3 He and 3 He- 4 He. Among the principal suppliers of spectroscopic data on such unbound atomic pairs, one can find mature areas of scientific inquiry, viz., collision-induced Raman scattering 9,10,15,[23][24][25] and absorption 8,21,[26][27][28][29] as well as the process of collision-induced hyper-Rayleigh scattering which is a younger area in this list. 19 Not unrelated to this issue is the use of cold elastic scattering [30][31][32][33] as an observational means to assess the interaction potential of He-He.…”

Recent advances in collisional effects on spectra of molecular gases and their practical consequences

“…42 and the collision-induced light scattering, has been studied in pure H 2 [399] and in a H 2 -Xe mixture [400].…”