  The local environment of manganese atoms in LaMnO3 under pressure up to 15.3
GPa has been studied by x-ray absorption spectroscopy. For pressures below 8
GPa, no change is detected within the MnO6 octahedra. Above this pressure a
continuous reduction of the long Mn-O distance takes place, however the
octahedral distortion persists over the whole pressure range. At 15.3 GPa the
average Jahn-Teller splitting of the distances is reduced by about one third,
indicating that a total removal of the local Jahn-Teller distortion would occur
only for pressures around 30 GPa, where metallization is reported to take
place. A hysteresis in the long distance reduction is observed down to ambient
pressure, suggesting the coexistence of MnO6 distorted and undistorted units.
