Electron nuclear dynamics studies of H3 and H3+

The electron nuclear dynamics (END) theory is used to study various processes involving the disintegration of a H-3 and the pseudorotation of the H-3(+) ion. The former system is prepared in an initial state of equilateral geometry which is associated with a degeneracy of the electronic system. The electronic wave function is initially defined as a representation of either of the D-3h doublet components; the corresponding dynamical features are considered in terms of nuclear trajectories for both cases. Disintegration out of a rotating state is shown to yield periodic electronic spin exchange between two bonding H atoms, which is interpreted as a signature of nonadiabatic behavior. Possible applications of this phenomenon in the study of molecular dissociation is discussed. The bound system H-3(+) is explored under the aspect of pseudorotational motion. Different dynamic regimes are explored; it is shown that the limiting case of circular pseudorotation can be approximated through the choice of an initial nuclear distortion momentum of magnitude P approximate to 1.7 au. For sizably smaller momenta, the motion is dominated by one distortion mode only; for larger momenta, pseudoprecession results. These dynamic phenomena find their electronic counterparts in cyclical charge waves excited in the electronic system. (C) 1999 John Wiley & Sons, Inc. Int J Quant Chem 75: 367-383, 1999.