The prediction of the nuclear quadrupole splitting of 119Sn Mössbauer spectroscopy data by scalar relativistic DFT calculations.

The electric field gradient components for the tin nucleus of 34 tin compounds of experimentally known structures and (119)Sn Mössbauer spectroscopy parameters were computed at the scalar relativistic density functional theory level of approximation. The theoretical values of the electric field gradient components were used to determine a quantity, V, which is proportional to the nuclear quadrupole splitting parameter (DeltaE). In a subsequent linear regression analysis the effective nuclear quadrupole moment, Q, was evaluated. The value of (11.9+/-0.1) fm(2) is a significant improvement over the non-relativistic result of (15.2+/-4.4) fm(2) and is in agreement with the experimental value of (10.9+/-0.8) fm(2). The average mean square error DeltaE(calcd)-DeltaE(exptl)=+/-0.3 mm s(-1) is a factor of two smaller than in the non-relativistic case. Thus, the approach has a quality which provides accurate support for the structure interpretation by (119)Sn spectroscopy. It was noted that geometry optimization at the relativistic level does not significantly increase the quality of the results compared with non-relativistic optimized structures. The accuracy in the approach called on us to consider the singlet-triplet state nature of the electronic structure of one of the investigated compounds.