CLASSICAL TRAJECTORY AND ADIABATIC CHANNEL STUDY OF THE TRANSITION FROM ADIABATIC TO SUDDEN CAPTURE DYNAMICS .3. DIPOLE-DIPOLE CAPTURE

Classical trajectory (CT) calculations of dipole-dipole capture proces ses are performed over wide ranges of conditions. Besides the anisotro pic dipole-dipole potential, an isotropic dispersion potential is acco unted for. The Massey parameter of the system characterizes the transi tion between adiabatic and nonadiabatic (sudden) dynamics. In the adia batic limit, under classical conditions, CT and statistical adiabatic channel model (SACM) give identical thermal capture rate constants whi ch can be expressed in simple parametrized form The transition from qu antum to classical SACM rate constants is represented analytically as well. Furthermore, harmonic oscillator versions of SACM for dipole-dip ole capture are compared with the corresponding models for ion-dipole and ion-quadrupole capture. (C) 1996 American Institute of Physics.