Via CASSCF/MRCI and RSPT2 calculations (single and double excitation with Davidson correction) the potential en - ergy curves of 20 electronic states in the representation 2S+1 Λ （±） of the molecule SiO have been calculated. By fitting these potential energy curves to a polynomial around the equilibrium internuclear distance r e , the harmonic frequency ω e , the rotational constant B e , and the electronic energy with respect to the ground state T e have been calculated. For the considered electronic states the permanent dipole moment μ have been plotted versus the internuclear distance r . Based on the canonical functions approach, the eigenvalues E v , the rotational constant B v and the abscissas of the turning points r min and r max have been calculated. The comparison of these values to the experimental and theoretical results available in the literature is presented. In the present work 8 higher electronic states have been studied theoretically for the first time.
Keywords<i>Ab Initio</i>CalculationSiO MoleculePotential Energy CurvesSpectroscopic ConstantsDipole MomentRovibrational Calculation
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