SOME PROPERTIES OF THE LOWER ELECTRONIC STATES FOR NONLINEAR HE-3(+) CLUSTERS

Accurate, highly correlated calculations have been carried out for the ground electronic state and for a few of the lower excited electronic states, two of which are discussed in this work, of the trimer ionic helium cluster. Both linear asymmetric and nonlinear, symmetric, and a symmetric, configurations have been considered over a rather broad ran ge of nuclear geometries. The results confirm the experimentally found [Chem, Phys. 102, 2773 (1995)] fragmentation patterns involving He an d He+ fragments only and further suggest a range of possible nuclear g eometries from which nonadiabatic couplings could also lead to He-2(+) fragments, albeit with a lower probability than the former channels. (C) 1997 American Institute of Physics.