Method of Diatomics-in-Molecules. VII. Excited Singlet States of H3+

Abstract

Diatomics‐in‐molecules theory is applied to the excited singlet‐state functions of H3 + which are anti‐symmetric to the molecular plane. If one uses only 1s and 2p AO's, it is possible to construct six covalent singlet valence‐bond wavefunctions of this type, and this set reduces to 1 A 2 ″ + 1 A 1 ″ + 2 1 E″ for equilateral triangles, 3 1 A 2 + 3 1 B 1 for isosceles triangles, or one component of each of 3 1 Π g + 3 1 Π u for linear symmetrical H3 +. Potential‐energy surfaces for all states have been computed. None of the states appear to be stable or metastable. For the lowest energy 1 A 2 ″ state for equilateral H3 +, the diatomics‐in‐molecules results agree with a previous extensive ab initio calculation by Conroy within 7 kcal.