Determination of the collision-induced depolarized Raman light scattering cross section of the argon diatom

Abstract

We report two independent calibrations of the argon diatom Raman light scattering cross section at 20 cm−1 shift (Stokes side), based on rotational Raman lines of hydrogen and nitrogen as an external reference standard. The precision is about 5% on an absolute scale, and the agreement relative to each other even better. The excitation wavelength is 5145 Å, but calibrations at 4880 and 4579 Å are seen to be consistent if the dominating factor 1/λ4 (λ = wavelength) is accounted for. Thus, a useful secondary standard for the calibration of similar spectra is obtained, and a long-standing question as to the absolute value of the diatom scattering cross section appears to be settled.