AB-INITIO COLLISION-INDUCED POLARIZABILITY, POLARIZED AND DEPOLARIZEDRAMAN-SPECTRA, AND 2ND DIELECTRIC VIRIAL-COEFFICIENT OF THE HELIUM DIATOM

Symmetry-adapted perturbation theory has been applied to compute the i nteraction-induced polarizability for the helium diatom. The computed polarizability invariants have been analytically fitted, and used in q uantum-dynamical calculations of the binary collision-induced Raman sp ectra. The predicted intensities of the depolarized spectrum are in go od agreement with the experimental data [M.H. Proffitt et al., Can. J. Phys. 59, 1459 (1981)]. The computed polarized spectrum shows agreeme nt with the experiment within the large experimental uncertainties. Th e calculated trace polarizability was also checked by comparison of co mputed second dielectric virial coefficients with the experimental dat a. The ab initio dielectric virial coefficients, including first and s econd quantum corrections, agree well with the experimental data from indirect measurements. (C) 1996 American Institute of Physics.