ON THE DYNAMICS OF FREE-RADICAL DISPROPORTIONATION REACTIONS

Using ab initio potential surfaces, classical (co-planar) trajectory calculations were made for the combination of H + BeH and of CH + CH. For the former reaction, disproportionation to H2 + Be was rare, occurring only for a linear H...H...Be configuration. Likewise, in the second case, the formation of CH2 + C occurs only via a direct reaction. The principal mechanism in the CH + CH reaction is to form [C2H2]*, which dissociates into C2H + H, or very occasionally, directly into C2 + H2. If the energy is very high, the C2H radical can dissociate into C2 + H, but sometimes [C2H2]* itself may dissociate simulataneously into C2 + H + H.