Knowledge Bank

The equilibrium geometry and barrier height to inversion of $H3O+$ have been calculated by CEPA using a large basis set of 103 contracted Gaussian type orbitals. The results are: $re=0.9745\backslash AA.\theta e=16.94\backslash AA$, and BH (barrier height) $=679cm-1$. These results are in very good agreement with the values deduced from laser IR spectroscopy by Sears $etal.1$ The proton affinity of $H2O$ at zero temperature is calculated to be 687 kJ $mo1-1$ and lies within the error bars of the experimental value of Ng $etal.2$ $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$ T. J. Sears, P. R. Bunker, P. B. Davies, S. A. Johnson, and V. Spirko, J. Chem. Phys. 83, 2676(1985). $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ C. Y. Ng, D. J. Trevor, P. W. Tiedemann, S. T. Ceyer, P. L. Kronebusch, B. H. Mahan, and Y. T. Lee, J. Chem, Phys. 67, 4235 (1977).