The H2O++ Ground State Potential Energy Surface

✍ Scribed by P.R. Bunker; Ota Bludsky; Per Jensen; S.S. Wesolowski; T.J. Van Huis; Y. Yamaguchi; H.F. Schaefer III

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 97 KB
• Volume: 198
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.7970

✦ Synopsis

At the correlation-consistent polarized-valence quadruple-zeta complete active space self-consistent field second-order configuration interaction level of ab initio theory (cc-pVQZ CASSCF-SOCI), we calculated 129 points on the ground electronic state potential energy surface of the water dication H(2)O(++); this calculation includes the energy of;X(3)Sigma(-) OH(+) at equilibrium and the energy of the triplet oxygen atom. We determined the parameters in an analytical function that represents this surface out to the (OH(+) + H(+)) and (O + 2H(+)) dissociation limits, for bending angles from 70 to 180 degrees. There is a metastable minimum in this surface, at an energy of 43 600 cm(-1) above the H(+) + OH(+) dissociation energy, and the geometry at this minimum is linear (D(infinityh)), with an OH bond length of 1.195 Å. On the path to dissociation to H(+) + OH(+), there is a saddle point at an energy of 530 cm(-1) above the minimum, and the geometry at the saddle point is linear (C(infinity Kv)) with OH bond lengths of 1.121 and 1.489 Å. Using the stabilization method, we calculated the lowest resonance on this surface. Relative to the metastable local minimum on the potential energy surface, the position of the lowest resonance for H(2)O(++), D(2)O(++), and T(2)O(++) is 1977(85), 1473(25), and 1249(10) cm(-1), respectively, where the width of each resonance (in cm(-1)) is given in parentheses. Copyright 1999 Academic Press.