M-dependence of collisional transfer of rotational energy in methyl alcohol: the (4−1 ← 30)p – (40 ← 31)s system

An M-resolved microwave double resonance study of collision-induced rotational energy transfer has been carried out for the (4−1 ← 30)p – (40 ← 31)s four-level system of CH3OH. Spectra are reported for each distinct combination of pump and signal M-components. The observed M-dependence of the double resonance signals is in good agreement with a very simple model of the collisional transfer in which a transition rate constant is taken to depend only on the square of the dipole matrix element for the transition.