THE INVERSION MECHANISM FOR THE REACTION H+CD4-]CD3H+D

The reaction H + CD4 --> CHD3 + D is shown to take place by an inversion mechanism. The evidence is as follows. When the H atom has an anisotropic (perpendicular) velocity distribution, the D atom velocity distribution is also perpendicular. For a relative energy near 2 eV, the reaction cross section for H + CD4 is 0.084 +/- 0.014 A2 and for H + CH3D is 0.040 +/- 0.015 A2. At the same H atom energy, when CH3CD3 is substituted for CD4, no D atoms can be detected. Finally, around 80% of the initial H atom kinetic energy is released as kinetic energy of the D atom showing that the reaction is nearly vibrationally adiabatic.