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

The electric field gradient components for the tin nucleus of 34 tin compounds of experimentally known structures and 119Sn 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 (ΔE). In a subsequent linear regression analysis the effective nuclear quadrupole moment, Q, was evaluated. The value of (11.9 ± 0.1) fm2 is a significant improvement over the non-relativistic result of (15.2±4.4) fm2 and is in agreement with the experimental value of (10.9 ± 0.8) fm2. The average mean square error ΔEcalcd- ΔEcalcd = ±0.3 mms-1 is a factor of two smaller than in the nonrelativistic case. Thus, the approach has a quality which provides accurate support for the structure interpretation by 119Sn 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 singlettriplet state nature of the electronic structure of one of the investigated compounds.