HYDROGEN AND HELIUM PRESSURE BROADENING OF CH3F BETWEEN 1 K AND 600 K

The hydrogen (H-2) and helium (He) pressure broadening cross sections have been measured between 1 and 600 K for the J = 2-3, K = 0 and J = 1-2, K = 0 transitions of CH3F, respectively. This two and a half decade range in temperature makes possible the consideration of these collisions as a spectroscopic process in which the translational energy plays the role of the spectroscopic variable. For the collisions studied here the pressure broadening cross section is slowly varying in the semi-classical region above approximate to 100 K, but at lower temperature the cross sections change rapidly, with significant collision pair specific differences.