## isomer shift

in Mössbauer spectroscopy
https://doi.org/10.1351/goldbook.I03296
Measure of the energy difference between the source ($$E_{\text{s}}$$) and the @A00034@ ($$E_{\text{a}}$$) transition. The measured Doppler velocity shift, $$\delta$$, is related to the energy difference by $E_{\text{a}}- E_{\text{s}}=\frac{\delta \ E_{\gamma }}{c}$ where $$E_{\gamma }$$ is the Mössbauer gamma energy and $$c$$ is the speed of light in vacuum.
Source:
PAC, 1976, 45, 211. (Nomenclature and Conventions for Reporting Mössbauer Spectroscopic Data) on page 214 [Terms] [Paper]