Studies of the Interaction between Stable Molecules and Atoms. V. Molecular Orbital Approach to the H+H2 Reaction

Abstract

In an attempt to find a relatively simple way of calculating activation energies for chemical reactions, Roothaan's LCAO‐SCF method has been applied to the linear H₃ complex. Since Roothaan's method has been developed for closed shells, a self‐consistent field treatment has been done on the linear H₃^— complex. According to Roothaan, the energy of the H₃ should be equal to a first approximation to the energy of the H₃^— minus the energy required to remove one electron. Calculations have been made at distances ranging from 1.4 to 2.5 atomic units and for various values of the screening constant. Correlation diagrams for the reaction H+H₂ have been constructed and the activation energy calculated. The method gives considerable insight into charge distribution but is unsatisfactory for calculating good energy values. The results are compared with experiment and with values calculated by the MO‐configuration interaction method which yields a value of 8.76 kcal/mole.