Synchrotron Radiation-Based Quasi-Elastic Scattering Using Mössbauer Gamma Ray with neV-Energy Resolution

Abstract

Gamma rays of energy 14.4 keV from excited 57 Fe nuclei show a very narrow energy width of 4.67 neV by the Mössbauer effect. Mössbauer gamma rays are utilised as probe beams in unique quasi-elastic scattering spectroscopy with neVenergy resolution. The technique enables measurements of atomic/molecular dynamics on timescales between nanoseconds and microseconds for various condensed matter systems, such as supercooled liquids, glasses and soft materials. The microscopic dynamics is measured in time domain or energy domain based on synchrotron radiation using a time-domain interferometer or a nuclear Bragg monochromator, respectively. We introduce state-of-the-art spectroscopic techniques, application results and future perspectives of quasi-elastic Mössbauer gamma ray scattering based on synchrotron radiation.

Dynamics Study of Superionic Conducting Glass Na3PS4 Using Quasi‐Elastic Gamma‐Ray Scattering: Analysis Based on Diffraction and Reverse Monte Carlo–Density Functional Theory Modeling

“…Directional Mössbauer gamma rays (with an energy of 14.4 keV and energy width of ≈4.7 neV) from the 57 Fe first nuclear‐excited state generated by synchrotron radiation were utilized for the QEGS measurements using multi‐line time‐domain interferometry. [ 13,14 ] Incident synchrotron radiation with a bandwidth Δ E of 3.5 meV of full width at half maximum at the nuclear resonant energy was obtained using a high‐resolution monochromator comprising Si (5, 1, 1) and Si (9, 7, 5) crystals. We used a double‐stacked eight‐element Si‐avalanche photodiode (APD) detector.…”

“…Several calibration spectra were measured before the experiment on the sample by following the standard experimental procedure. [ 13,14 ]…”

“…Recently, quasi‐elastic gamma‐ray scattering (QEGS) using time‐domain interferometry has become available for application studies. [ 11–14 ] QEGS allows us to measure experimental ISF, , which includes the effect of electron density distribution in atoms at unique time scales between nanosecond and microsecond. [ 13,14 ] In addition, QEGS can determine the value at subpicosecond time scale.…”

“…[ 11–14 ] QEGS allows us to measure experimental ISF, , which includes the effect of electron density distribution in atoms at unique time scales between nanosecond and microsecond. [ 13,14 ] In addition, QEGS can determine the value at subpicosecond time scale. [ 13,14 ] Here, can be divided into partial ISFs, which include partial structural dynamics information of each atomic specie, similar to the case of SSF, which can be divided into partial SSFs.…”

“…[ 13,14 ] In addition, QEGS can determine the value at subpicosecond time scale. [ 13,14 ] Here, can be divided into partial ISFs, which include partial structural dynamics information of each atomic specie, similar to the case of SSF, which can be divided into partial SSFs. It is essential to understand the temporal behavior (e.g., relaxation and oscillation) of each partial ISF to reveal the microscopic dynamics of respective relaxation units in the system.…”