Polarizedhyphen;orbital valencehyphen;bond calculations on the ground state properties ofH5plus;

摘要

Ab initiocalculations were made onH5plus;in order to predict its equilibrium geometry, binding energy, vibrational frequencies, and enthalpy of formation. The method was based on a valencehyphen;bond configuration interaction wavefunction built from linear combinations of Gaussian basis orbitals and polarized by Sambe's method. Optimization of nonlinear parameters was handled by a conjugate directions procedure derived from Powell's and Zangwill's work.H5plus;was found to have aC2ngr;geometry in agreement with Esterfield and Linnett and with Huang, Schwartz, and Pfeiffer. The binding energy was estimated to be approximatelyDeequals; 0.1 eV and the enthalpy of formation fromH3plus;and H2to be about Dgr;Hequals; minus; 3.3 kcalsol;mole, which is the same order of magnitude as experimental measurements. The importance of doubly occupied structures and of polarization was assessed from our wavefunctions.