On the potential energy surface for collinear OH2+ (4Σ-)
Abstract
The potential energy surface for collinear OH2+ (4Σ-) has been investigated at the configuration interaction (CI) level using large primitive basis sets of Gaussian type orbitals (GTO) and the general atomic natural contraction (ANO). The CI calculations were carried out using the CIPSI algorithm and the accuracy established by comparison with full CI (FCI) test calibrations on the atoms and molecules of interest in the present work. For the reaction O+ ( 4Su ) + H2 (1Σ g+) → OH+ (3Σ -) + H(2Sg) the calculated value for the energy change of the reaction (ΔE) is - 0.30 eV to be compared with an experimental value of - 0.45 eV. The error in ΔE arises from the error in the ionization potential of oxygen and does only affect the reactants but not the products, while the discrepancy with the experiment is limited by the finite size of the basis set and not by truncations on the CI expansion. The collinear OH2+ minimum has been found to lie 0.338 eV below the products with an estimated accuracy of 0.01 eV. © 1991 American Institute of Physics.