Observation of a low spin state of iron in olivine by Moessbauer effect

The results of the application of Moessbauer spectroscopy in the study of two olivine samples formed under different geological conditions are presented. The Moessbauer spectrum of the first sample at room temperature showed a single quadrupole split doublet having a quadrupole splitting (QS) of 2.99 +- 0.88 mm/sec and an isomer shift (IS) of 1.22 +- 0.88 mm/sec. The spectrum of the second sample showed three peaks at velocities of 2.76, -0.12 and -2.84 mm/sec. The central peak was wider and more intensive than the outer ones, which indicated that it was composed of two superimposed peaks. The values of QS and IA obtained for the first sample are characteristic of the Fe2+ ion at a distorted octahedral site. These results are in good agreement with the results published earlier. The values of QS and IS obtained for the second sample are identical with those obtained for the first sample, i.e., characteristic of the high spin Fe2+ ion at a distorted octahedral site, which is the normal result expected for olivine. (Z.S.)