Relativistic Jahn–Teller Effect in Molecules with Point Symmetry D4h

The paper considers the relativistic multimode Jahn–Teller effect 2 E u × ( b 1 g + b 2 g + e u ) for square molecular complexes with a heavy central atom and an odd number of electrons. All the 32 elements of the double symmetry group D′ 4 h , are determined that which are space-matrix operators. A vibronic 4 × 4 matrix is obtained in the quadratic approximation with respect to the normal modes for the contributions of the electrostatic Hamiltonian and in the linear approximation for the contributions of the spin–orbit coupling. Fourmode potential energy surfaces are presented in the form of analytical expressions.