Spectral characteristics of the excitation of SF6 molecules by an intense infrared laser field under strong cooling conditions

A study was made of the fine structure of the excitation of the lower vibrational levels in SF6 molecules gasdynamically cooled to temperatures of the order of 30 K. A two-frequency infrared–infrared laser excitation method was employed. A continuously tunable CO₂ laser was used for the first stage. At a frequency of 944.39 cm^–1 a contrast absorption peak was detected, having a width of less than 0.1 cm^–1 and corresponding to the A_1g two-photon resonance.