Ab initio and density functional study of spectroscopic properties of CuO and CuS

Spectroscopic constants and molecular properties of CuO and CuS in their ground state have been studied in detail using B3LYP, MP2 and CCSD(T) methods. The basis set has been designed by testing the convergence and consistency of the calculated spectroscopic properties of these molecules and the final basis set is used for this calculation. The basis set of Cu (7s6p4d2f) has been built upon the basis set (6s3p3d) of Ahlrichs et al. and the basis sets for oxygen and sulfur are correlation consistent basis set. The spectroscopic properties of CuO and CuS obtained with CCSD(T) method in conjunction with these basis sets agree well with the experimental values wherever available for comparison. Most of the spectroscopic properties of CuO and CuS are new. The spectroscopic properties of CuS are first reported theoretically.