“…The underestimation of force constants by the PBE functional relative to NRIXS measurements has also been found in minerals of other Mössbauer-active elements such as Fe and Eu. Nie et al and Heard et al summarized the average Fe force constants in minerals (i.e., hematite, goethite, ferrihydrite, almandine, ilmenite, annite, schorl, fayalite, and greenalite) obtained from the PBE(+U) calculations and NRIXS measurements in their and previous studies (DFT: refs , . NRIXS: refs , .…”