Multireference coupled-pair approximation study of the CuSi molecule

Research paper by Mutsumi Tomonari, Yuji Mochizuki, Kiyoshi Tanaka

Indexed on: 01 Apr '99Published on: 01 Apr '99Published in: Theoretical Chemistry Accounts


The electronic structure of the CuSi molecule was examined using the multireference coupled pair-approximation (MRCPA) following multireference single and double excitation configuration interaction calculations. We found the ground state to be the 2Π state, and we evaluated the bond length, dissociation energy, vibrational frequency, and dipole moment for the 2Π ground state and for low-lying 4Σ− and 2Δ excited states. The dissociation energy of the 2Π ground state by MRCPA is 2.13 eV, which agrees well with the experimental value of 2.26 eV. The inclusion of higher excitations by MRCPA significantly improves the description of the bonding and the accuracy of the spectroscopic constants.