Frequency-dependence of the polarizability anisotropy of CO 2 revisited

We present extended determinations of the polarizability anisotropy κ(ω) of CO₂ at 514.5 and 488.0 nm by means of measuring the depolarization ratio ρ(ω) of linearly polarized laser light. Taking into account the hitherto reported data on ρ(ω) as well as experimental data on the mean polarizability α(ω) and additional information derived from Kerr-effect measurements, we obtain a value of the static polarizability anisotropy of CO₂ of κ(0)=15.2(1.6) au. The large uncertainty of ≈10% results from the fact that all available experimental information is used to obtain an estimate of the static polarizability ansiotropy of CO₂. This zero-frequency value, which includes the vibrational part of the static anisotropy, is in reasonable agreement with hitherto reported experimental data and in good accordance with new ab initio calculations.