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G.A. Adebayo: „Molecular Dynamics Simulation of Infrared and Absorption Spectra of MgO at High Temperature and Pressure”
Department of Physics, University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria

We calculate by molecular dynamics the optical functions of a compound in the far infrared region 100 - 1000 cm-1, for pressures up to 40 GPa and temperatures up to 4000 K. An ab intio parameterized many-body force field is used to generate the trajectories. Infrared spectra are obtained from the time correlation of the polarization, and from Kramers-Kronig relations. The calculated spectra agree well with experimental data at ambient pressure. We find that the infrared absorption of MgO at CO2 laser frequencies increases substantially with both pressure and temperature and we argue that this may explain the discrepancy among the melting curves of MgO determined in CO2 laser-heated diamond-anvil cell experiments and in theoretical calculations.