Hyper-Rayleigh light-scattering spectra determined byab initiocollisional hyperpolarizabilities ofHe−Neatomic pairs

Abstract

The collision-induced (CI) first hyperpolarizability tensor for the $\mathrm{He}\text{\ensuremath{-}}\mathrm{Ne}$ pair composed of the lightest noble gas elements has been obtained on the grounds of an ab initio method as a function of the interatomic distance $R$. Collision-induced hyper-Rayleigh (CIHR) spectra scattered in mixtures of such atoms at temperatures of 95 and $295\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ are computed in absolute units both quantum mechanically and classically for the frequency shifts up to $1000\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$. The spectral features of the CIHR profiles due to the vector ${b}_{1}$ and septor ${b}_{3}$ parts of the hyperpolarizability tensor are discussed. The quantum character of computed spectra, especially significant at lower temperatures, has been found out. The integrated intensities of the spectra have been evaluated and used as a criterion of the reliability of the computed profiles. The frequency-dependent depolarization ratio of the CIHR spectra was evaluated and discussed. The properties of the resulting HR profiles have been compared with the depolarized CI Rayleigh spectrum of the $\mathrm{He}\text{\ensuremath{-}}\mathrm{Ne}$ pair.