LPHON_READ_FORCE_CONSTANTS

LPHON_READ_FORCE_CONSTANTS = .TRUE. | .FALSE.

Default: LPHON_READ_FORCE_CONSTANTS

= .FALSE.

Description: LPHON_READ_FORCE_CONSTANTS read the force constants from a vaspin.h5 file containing the force constants computed with a previous VASP run.

After the computation of the force constants using finite-differences (IBRION=5,6) or density-functional perturbation theory (IBRION=7,8) on a supercell the force constants are written to the vaspout.h5 file. To plot the phonon dispersion on a different path the user can modify the QPOINTS file and read the force constants computed previously (i.e. without performing the finite-differences computations on supercells again). To do so copy vaspout.h5 to vaspin.h5 and set LPHON_READ_FORCE_CONSTANTS=.TRUE. in the INCAR file. Note that when this is set only the phonon dispersion is performed and then VASP quits without running any additional calculation specified in the INCAR file.

Mind: Only available as of VASP 6.4.0.

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