Theoretical study of the nuclear spin-molecular rotation coupling for relativistic electrons and non relativistic nuclei

G. A. AUCAR; S. S. GÓMEZ; M. C. RUIZ DE AZÚA; C. G. GIRIBET

Riviera Maya

Congreso; XXXVII Congreso de Químicos Teóricos de Expresión Latina (Quitel 2011); 2011

A theoretical study of the relation between the relativistic formulation of the nuclear magnetic shielding and spin-rotation tensors is presented. To this end a theoretical expression of the relativistic spin-rotation tensor is formulated, considering a molecular hamiltonian of relativistic electrons and non-relativistic nuclei. Molecular rotation effects are introduced considering the terms of the Born-Oppenheimer decomposition which couple the electrons and nuclei dynamics. The loss of the simple relation linking both spectral parameters in the non relativistic formulation is further analyzed carrying out a perturbative expansion of relativistic effects by means of the linear response within the elimination of the small component (LRESC) approach. It is concluded that relativistic effects on the spin-rotation tensor are less important than those of the nuclear magnetic shielding tensor. A qualitative analysis of the role of inner shell and valence orbital electrons is carried out and numerical calculations were carried out in model systems in order to establish the suitability of this formalism to correctly reproduce experimental results.