Measuring the Molecular Polarizability of Air

2009/07/06 by M. J. Madsen, Madsen, M. J., Daniel R. Brown +5
Chemistry · Decision Sciences · Physics and Astronomy · #FOS: Physical sciences #Mechanical and Optical Resonators #Optics (physics.optics) #Physics Education (physics.ed-ph) #Scientific Measurement and Uncertainty Evaluation #Spectroscopy and Laser Applications

paper · pdf · doi:10.48550/arxiv.0907.0782

openalex publication_date 2009/07/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We present an update of the "refractive index of air" experiment commonly used in optics and undergraduate advanced labs. The refractive index of air is based on the average molecular polarizability, which we measured from the period of the phase shift in a Michelson interferometer as a function of pressure. Our value of the average molecular polarizability of air is γ_mol = 2.133 ± 0.032 × 10^-29 m³ (95% CI) and from this we find the refractive index of air at atmospheric pressure to be n = 1.0002651(66), which is in agreement with the accepted value of n=1.000271375(6).

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