Biomedical subjects
Publications and source records attributed to L F Errea.
A parametrization of the three asymptotic conical intersections between the energies of the H3(+) ground state and the first excited singlet state is presented. The influence of an additional, fourth conical intersection between the first and second excited states at the equilateral geometry on the connection between the three conical regions is studied, for both diatomics-in-molecules and ab initio molecular data.
The lowest two ab initio potential energy surfaces (PES), and the corresponding nonadiabatic couplings between them, have been obtained for the H3+ system; the molecular data are compared to those calculated with the diatomic in molecules (DIM) method. The form of the couplings is discussed in terms of the topology of the molecular structure of the triatomic. The method of Baer is employed to generate "diabatic" states and the residual nonadiabatic couplings are calculated. The ab initio results for these are markedly different from the corresponding DIM data, and show the need to consider the third PES.
We present a method to ensure the sign consistency of dynamical couplings between ab initio three-center wave functions. The method also allows to systematically "diabatize" avoided crossings between two potential energy surfaces, including conical intersections. Illustrations are presented for H(3)(+), LiH(2)(+), and NH(2)(5+) quasimolecules.