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

Abstract

The collision-induced ͑CI͒ first hyperpolarizability tensor for the He-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 ͑CIHR͒ spectra scattered in mixtures of such atoms at temperatures of 95 and 295 K are computed in absolute units both quantum mechanically and classically for the frequency shifts up to 1000 cm −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 He-Ne pair.

Applying Conventional Ab Initio and Density Functional Theory Approaches to Electric Property Calculations. Quantitative Aspects and Perspectives

“…We single out a few significant papers related to the above field. Głaz et al [71] reported a study of the collision-induced hyper-Rayleigh light-scattering spectra of He-Ne atomic pairs. Chrysos et al [72] reported a study of the CO 2 -Ar collision-induced n 3 CO 2 band.…”

Collision-induced hyper-Rayleigh light scattering in gaseous dihydrogen-neon mixtures

“…Indeed, light losses due to the experimental optical setup can be important and, at least, we must consider the upper order of magnitude to be 10 −82 cm 8 s erg −1 . However, this shows that the HR spectra recently studied by our group in a purely theoretical way could be scanned experimentally in a wide frequency range relative to the central frequency 2ν L [14][15][16][17]. This would offer the possibility of extracting from the spectra crucial information about the symmetry-adapted components, as we will see further in the case here considered, H 2 -Ne.…”

“…The blueprint for the presented study has four major steps following the footprints of our previous works: quantum chemistry (QC) ab initio calculations of the hyperpolarizability properties of the compound considered, evaluation of the symmetry-adapted components of the hyperpolarizability tensor and their fitted dependencies on the intermolecular distance R, translational spectral contribution computations, and finally, determination of the resulting full rototranslational lines of CIHR spectra [14][15][16][17][18][19].…”

“…We expect this choice to be particularly advantageous for a severe test of basis-set effects. We obtained the following interaction-induced hyperpolarizability values at the CCSD (full) level of theory: β zzz = 16.67 (basis A), 16.65 (basis B), and 16.64 (basis C). This remarkable stability is also present in calculations on the T-shaped system, at the same separation.…”

Structural distribution in mixed ternary noble gas and Lennard-Jones clusters

“…The interaction hyperpolarisability of He 2 , Ne 2 , and He 3 was discussed using an ab initio wave function, McWeeny's coupled Hartree-Fock perturbation theory and an efficient algorithm [8]. Furthermore, collision-induced hyper-Rayleigh spectra of Ne-Ar [9], He-Ne [10], and He-Ar [11] were computed, and the spectral features were discussed. The application of conventional generalized gradient approximation (GGA) and meta-GGA density functionals to van der Waals interactions is fraught with difficulties, and the PW86 exchange, combined with a dynamical correlation GGA and the Becke-Johnson dispersion model, yielded excellent results in noble gas diatomics [12].…”