Calculations for the transverse N-point phonons in bcc Zr, Nb, and Mo.

The frequencies of the transverse N-point phonons in Nb and Mo have been calculated using the first-principles frozen-phonon method. The ordering of the modes is reversed in these metals in agreement with experiment. Similar calculations for the L and T/sub 2/N-point phonons in the high-temperature bcc phase of Zr agree with recent measurements, while the results for the T/sub 1/ phonon of Zr indicate an instability toward the formation of the hcp phase.