Interpretation of the 119Sn Moessbauer parameters

The variations of the 119Sn Moessbauer isomer shift δ are interpreted for tin compounds from a semi-empirical tight-binding calculation of the electronic density at the nucleus ρ(0). A molecular model is proposed in order to relate the variations of ρ(0) for the Sn(IV) chalcogenides to the changes in the Sn environment. The variations of the experimental values of the quadrupole splitting δ are linearly correlated to the values of the electric field gradients (EFG) calculated by the full-potential linearized-augmented-plane-wave (FP-LAPW) method. The value of the 119Sn nuclear quadrupole moment is found to be vertical bar Q vertical bar = 10.5 ± 0.2 fm2. Finally, the relation between the EFG and the Sn environment is discussed for SnO