Spin-orbit splitted excited states using explicitly-correlated equation-of-motion coupled-cluster singles and doubles eigenvectors
Denis Bokhan 1∗ , Dmitrii N. Trubnikov 1 , Ajith Perera2 and Rodney J. Bartlett 2
1 Laboratory of molecular beams, Physical Chemistry Division, Department of Chemistry, Moscow Lomonosov State University, Moscow, Russian Federation, 119991
2 Quantum Theory Project, University of Florida, Gainesville, Florida, 32611, USA
Email: denisbokhan@mail.ru
An explicitly-correlated method of calculation of excited states with spin-orbit couplings, has been formulated and implemented. Developed approach utilizes left and right eigenvectors of equation-of- motion coupled-cluster model, which is based on the linearly approximated explicitly correlated coupled- cluster singles and doubles [CCSD(F12)] method. The spin-orbit interactions are introduced by using the spinorbit mean field (SOMF) approximation of the Briet-Pauli Hamiltonian. Numerical tests for several atoms and molecules show good agreement between explicitlycorrelated results and the corresponding values, calculated in complete basis set limit (CBS); the highly-accurate excitation energies can be obtained already at triple-ζ level.