| SM ISO690:2012|
TSUKERBLAT, Boris; PALII, Andrew; CLEMENTE-JUAN, Juan; CORONADO, Eugenio. Symmetry assisted approach to the non-adiabatic vibronic problem: advances and challenges . In: Materials Science and Condensed Matter Physics. Editia a 7-a, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, p. 30.
|Materials Science and Condensed Matter Physics
Editia a 7-a, 2014
Conferința "Materials Science and Condensed Matter Physics" |
Chișinău, Moldova, 16-19 septembrie 2014
In context of the present-day trends in the studies of the nanosized systems which are at the border between classical and quantum scales here we present a symmetry assisted approach aimed to the accurate solution of the non-adiabatic vibronic Jahn-Teller (JT) problem in large scale multimode systems, like impurity centers and clusters in crystals, molecular and biological objects, etc. For the systems at nanoscale the classical approaches fails meanwhile within the quantum-mechanical treatment we face a very high dimension of the Hilbert space aggravated by a poor convergence of the computational procedure with the truncated electron-vibrational basis. The system under consideration is supposed to consist of the set of the electronic levels of definite symmetries mixed by the active JT vibrational modes. The proposed algorithm for the solution of the JT problem takes full advantage from the point symmetry arguments. We develop a special algorithm for the design of the symmetry adapted electron-vibrational basis with the aid of the subsequent application of the special operators (which we call mult-ivibronic operators) based on the subsequent multiple Clebsch-Gordan coupling with the Gram-Schmidt orthogonalization of the basis at each step  of the procedure. Finally, the generated vibrational basis is coupled to the electronic ones to get the symmetry adapted basis in which the full matrix of the JT Hamiltonian blocked to the maximum extent. The general approach is applied to the evaluation of the hybrid electron-vibrational states and intervalence optical absorption in mixed valence systems containing arbitrary number of the localized spins and itinerant electrons. In particular, we discuss [2,3] the intriguing magnetic properties of the 2e-reduced MV dodecanuclear Keggin anion in which the electronic pair is delocalized over twelve sites (Td) giving rise to the (1T2+1E+1A1) (e+t2) (3T1+3T2) (e+t2) combined JT/pseudo JT problems for the spin-singlet and spin-triplet states. We report also the evaluation of the charge distribution and electronic and vibronic levels of mixed-valence tetra-ruthenium systems assembled as two coupled Creutz-Taube complexes for which the pioneering concept (exploration of bistable charge distribution rather than qubits) of implementations as molecular quantum-dot cellular automata was recently proposed and widely discussed. The financial support of the Israel Science Foundation is gratefully acknowledged (ISF, grant no. 168/09).