Electric polarizabilities of CH 4 , CO, and O 2 determined by an optical refractometer

Abstract We report high-precision measurements of the static electric dipole polarizabilities for methane (CH 4 ), carbon monoxide (CO), and oxygen (O 2 ) using an optical refractometer operating at 1566 nm. The dynamic polarizabilities at 1566 nm were converted to static polarizabilities via dipole oscillator strength distributions. The resulting static polarizabilities are 6.440 34(30) for CH 4 , 4.881 46(24) for CO, and 3.958 19(20) for O 2 , corresponding to relative standard uncertainties of 45 ppm, 49 ppm, and 46 ppm, respectively. The value obtained for O 2 shows excellent agreement with the literature value of 3.9582(2), while those for CH 4 and CO represent an improvement in precision by more than two orders of magnitude. These data provide a reliable benchmark for molecular polarizability calculations and contribute to accurate modeling of intermolecular dispersion forces and gas metrology.