# Measuring the Molecular Polarizability of Air - Physics > Optics

Abstract: We present an update of the -refractive index of air- experiment commonlyused in optics and undergraduate advanced labs. The refractive index of air isbased on the average molecular polarizability, which we measured from theperiod of the phase shift in a Michelson interferometer as a function ofpressure. Our value of the average molecular polarizability of air is\gamma mol = 2.133 \pm 0.032 \times 10^{-29} m^3 95% CI and from this we findthe refractive index of air at atmospheric pressure to be n = 1.000265166,which is in agreement with the accepted value of n=1.0002713756.

Author: M.J. Madsen, D.R. Brown, S.R. Krutz, M.J. Milliman

Source: https://arxiv.org/