Is There an Electronic Topological Transition in Zinc under High Pressure?

An electronic topological transition (ETT) in Zn was recently deduced from an anomaly in the Lamb-M\"ossbauer factor f at 6.6 GPa [Potzel et al., Phys. Rev. Lett. 74, 1139 (1995)]. We show by inelastic neutron scattering up to 9.4 GPa that the pressure dependence of the low energy acoustic phonon modes Σ₄, Σ₃, and T₄ is completely regular without any singularity over the entire pressure range. No phonon softening was found beyond 6 GPa, in contrast to the M\"ossbauer studies. Lattice dynamical calculations demonstrate that, in general, the strong decrease of f cannot be due to the q~0 phonon modes sensitive to the occurrence of an ETT.