Zinc-67 Mössbauer Spectroscopy

Computation of Mössbauer isomer shifts from first principles

“…This finding indicates a very high sensitivity of the chemical bonding in this compound to small structural changes. As a function of reduced cell volume we find the coupling to vary with a slope of −4.4 MHz, considerably less than the value reported from Mössbauer studies of −18.2 MHz [27]. Likewise, we find the valence density to change much more slowly with cell volume than literature reports, −2.00 ± 0.02 versus −10.7 ± 3.4 [27].…”

“…As a function of reduced cell volume we find the coupling to vary with a slope of −4.4 MHz, considerably less than the value reported from Mössbauer studies of −18.2 MHz [27]. Likewise, we find the valence density to change much more slowly with cell volume than literature reports, −2.00 ± 0.02 versus −10.7 ± 3.4 [27]. Given the success of the PAW method in computing the isomer shift and the electric field gradient (as measured by the above results for r 2 in 119 Sn and 67 Zn, and various reports for electric field gradients [16,17]), how can the sharp deviations for wurtzite ZnO be understood?…”

“…Then, from this information and the phonon eigenvectors, the mean square velocities were determined. For completeness we Shift data from [27]; computed second-order Doppler shifts and valence densities as described in the text and table 1. also calculated the Lamb-Mössbauer factors, which are related to the mean square displacements of the atoms and the photon wavevector.…”

“…Correlation of experimental67 Zn shifts corrected for the second-order Doppler shift with computed valence electron densities. Shift data from[27]; computed second-order Doppler shifts and valence densities as described in the text and table 1.…”

“…Experimental 67 Zn Mössbauer shifts from[27], and calculated valence electron densities, second-order Doppler shifts (S D ) and Lamb-Mössbauer factors (LMF). The valence densities are computed with the PAW scheme using the experimental crystal structures.…”