Renormalization of theH-point phonon anomaly in molybdenum

The frequency of the $H$-point phonon of molybdenum obtained from precise frozen-phonon calculations differs from the experimental value by 9%. An analysis of this unusually large discrepancy shows that nonadiabatic effects are small, while effects caused by the many-body renormalization of electronic states near the Fermi energy are of the same order of magnitude as the discrepancy.