Ab intio integrate multi-center orbitals method for large cluster systems: Total energy and normal vibration

A new computational scheme integrating multi-center ab initio molecular orbitals for determining total energy and normal vibration of large cluster systems is presented. The geometry parameters, the total energies, the relative energies, and the normal vibrations for four models of water cluster, the hydrated hydronium ion complex, and the transition state of proton transfer is calculated by the present method and are compared with those obtained by the full ab initio MO method.