Vibrational excitation of CH3F by collisions with ‘‘hot’’ hydrogen atoms

Infrared emission has been observed from CH3F collisionally excited by hot hydrogen atoms produced in the photolysis of H2S at 193 nm. The time-dependent emission at 2.5 (ν1+ν3, ν4+ν3), 3.3 (ν1, ν4), and 9.6 μm (ν3) has been analyzed, and both T-V and V–V energy exchange processes are observed. Relative populations of molecules excited into the ν3 and ν1, ν4 modes were determined; the population in the C–H stretching modes (ν1, ν4) is much lower than predicted by simple impulsive models of the collision process.