Calculations of potential energy surfaces in the complex plane. IV. Ab initio surfaces for H3+

Ab initio LCAO-MO-CI calculations are reported for selected geometries of H3+ in the vicinity of the real-valued avoided intersection and complex intersection. The complex energy difference between the two lowest singlet surfaces is compared to the corresponding DIM values. In addition, the effect of polarization functions in the basis set is investigated and atomic orbital electron populations for the complex CI wavefunction are determined.