NUCLEAR ELECTRIC FIELD GRADIENT AND MEAN SQUARE DISPLACEMENT OF IRON SITES IN SODIUM NITROPRUSSIDE

Both the electric-field-gradient (EFG) and mean square displacement (MSD) tensor parameters at the Fe sites in sodium nitroprusside at 23°C have been determined with a high precision by the Mössbauer technique. The EFG asymmetry parameter is =0.010.01. The principal axes of the two tensors do not coincide. Taking proper account of saturation effects was essential, even though the absorbers were only 0.2 mm thick. For the MSD, proper consideration of polarization effects was also important. A total of 34 runs on an absolutely calibrated mechanical drive gave for the quadrupole splitting EQ=1.70480.0025 mm/sec. © 1969 The American Physical Society.