This page gives hints on how to perform calculation with the extended FPMD model.
Extended First Principle Molecular Dynamics (Ext. FPMD) method allows to perform high temperature simulations from few Kelvins to thousands of eVs, by drastically reducing the needed number of bands for high temperature simulations. The implementation and usage will be described in an upcoming paper which is currently under review (Authors: A. Blanchet, J. Clérouin, M. Torrent, F. Soubiran).
High energy orbitals are replaced with pure single plane waves description based on the Fermi gas model. Bands from 1 to nband are treated with the complete plane waves basis set as usual, and the rest of occupied bands from nband to the infinity are treated with the Fermi gas model. Contributions to the energy, entropy, stresses, number of electrons and chemical potential are computed automatically after enabling the model with variable useextfpmd.
Contributions to the number of electrons and to the energy are explicitly shown in the _GSR.nc output file with key nelect_extfpmd and e_extfpmd (edc_extfpmd for the double counting term). The energy shift factor (resulting from the constant background potential) is also printed in the _GSR.nc output file with key shiftfactor_extfpmd.
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