Inelastic neutron scattering studies were performed on a powder and as
sembly of single crystals of La1.85Sr0.15CuO4. Phonon density of state
s and the Q-dependence of dynamic structure factor as well as the deta
ils of phonon scattering function were investigated as a function of t
emperature. We found specific phonon modes at the Brillouin zone cente
r and the zone boundary showed an anomalous behavior.