Complex formation, rearrangement, and reaction in PhOH++ND3:: Vibrational mode effects, recoil velocities, and ab initio studies

Vibrationally mode-selected phenol cations (C6H5OH+ and C6D5OH+) were reacted with ND3 in a guided-ion-beam instrument. Integral cross sections and recoil velocity distributions are reported as a function of collision energy and vibrational state. Three reactions are observed. A small signal is found for the [PhOH:ND3](+) adduct at low total energies, indicating the formation of a very long-lived complex. The major reaction is H/D exchange, generating PhOD++ND2H. Exchange is similar to 40% efficient at low energies, strongly inhibited by collision energy, and strongly enhanced by excitation of PhOH+ vibrations. Recoil velocity distributions suggest that H/D exchange proceeds through a statistical complex at all energies. A precursor complex is invoked to explain the energy and vibrational state dependence. The endoergic proton transfer reaction is a minor channel at all energies, with dynamics intermediate between the direct and complex limits. Quantum chemistry and RRKM calculations are reported, providing an additional mechanistic insight. (C) 2000 American Institute of Physics. [S0021-9606(00)01634-2].