ABINITIO CALCULATION OF THE DIPOLE-MOMENT AND FREQUENCY-DEPENDENT POLARIZABILITY FOR SILICON MONOXIDE AND ITS ANION

The potential energy curve and the bond-length dependence of the electric properties for SiO and its anion are calculated using ab initio MO methods. The static and frequency-dependent polarizabilities are evaluated directly from the large CI Hamiltonian matrix without the explicit knowledge of the eigenvectors of the matrix. Two states of the anion SiO- (2-SIGMA+ and 2-PI) lie closely by the ground state X(1)-SIGMA+ of SiO. The equilibrium internuclear distance R(e) of the 2-SIGMA+ state is nearly equal to that of the X(1)-SIGMA+ SiO state, while the R(e) of the 2-PI state is substantially longer than the latter. The electron affinity is estimated to be negative or nearly zero. The bond-length dependence of the dipole moment, the quadrupole moment and the polarizability tensor is expected to be remarkably different among three states X(1)-SIGMA+, 2-PI and 2-SIGMA+.