  High-pressure resistivity and x-ray diffraction have been measured on
La0.85MnO3-d. At low pressures the metal-insulator transition temperature (TMI)
increases linearly with pressure up to a critical pressure, P* ~ 3.4 GPa, which
is followed by reduction of TMI with increasing pressure. Analysis of the bond
distances and bond angles reveal that a bandwidth increase drives the in-crease
of TMI for pressure below P*. The reduction of TMI at higher pressures is found
to result from Jahn-Teller distortions of the MnO6 octahedra. The role of
anharmonic interatomic potential is discussed.
