INTERFEROMETRIC MEASUREMENTS OF THE DIPOLE POLARIZABILITY-ALPHA OF MOLECULES BETWEEN 300-K AND 1100-K .1. MONOCHROMATIC MEASUREMENTS AT LAMBDA=632.99 NM FOR THE NOBLE-GASES AND H-2, N-2, O-2, AND CH4

The temperature dependence of the dipole polarizability α(λ, T) of free atoms and molecules is determined by precise measurements of the refractive index n of gases in the extended temperature range between 300K and HOOK for wavelength λ = 632-99 nm, using a specially constructed Michelson twin interferometer, α of the noble gases is observed to be independent of T. α. of the molecular gases H2, N2, O2, and CH4 increases with increasing temperature by an amount of approximately 1 per cent per 1000 K. These results are in excellent agreement with theoretical predictions. They will be compared to previously measured temperature dependent polarizabilities. © 1990 Taylor & Francis Ltd.