The Unified Hamiltonian Formalism of Spin–Orbit Jahn–Teller and Pseudo-Jahn–Teller Problems in All Axial Symmetries

• DOI: 10.1021/acs.jctc.3c00782
• Publication Date: 2023-10-17T15:52:56Z
• Authors: Ekadashi Pradhan; Tao Zeng

Spatial degeneracy of electronic states closely connects spin-orbit coupling and vibronic coupling, which together determine properties of materials, especially heavy element compounds. Accurate description of those materials entails accurate mathematical formulas for spin-orbit vibronic Hamiltonians. For the first time ever, we in this work derive the Hamiltonian formalism to describe all spin-orbit Jahn-Teller and pseudo-Jahn-Teller vibronic problems in all axial symmetries. The conventional one-electron approximation of spin-orbit coupling, which was the foundation of all previous studies in this field, is not involved in the present work. Actually, the present formalism is applicable to all time-reversal symmetric hermitian Hamiltonian that has a Rank-1 dependence on the spin operator, without any restriction on the type and the number of term symbols and vibrational modes.