Interpretation of the Sn-119 Mossbauer parameters

The variations of the Sn-119 Mossbauer isomer shift delta are interpreted f or tin compounds from a semi-empirical tight-binding calculation of the ele ctronic density at the nucleus rho(0). A molecular model is proposed in ord er to relate the variations of rho(0) for the Sn(IV) chalcogenides to the c hanges in the Sn environment. The variations of the experimental values of the quadrupole splitting delta 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 Sn-119 nuclear qua drupole moment is found to be \Q\ = 10.5 +/- 0.2 fm(2). Finally, the relati on between the EFG and the Sn environment is discussed for SnO.