ABINIT Discussion Forums

Dear Sirs,

I have actually two questions concerning the pressure and stress tensor:
1) how the pressure and stress are actually calculated (is the implementation based on e.g. Nielsen&Martin, 1985);
2) and if it is possible to get a more verbose output about the contributions to the stress tensor (kinetic, hartree, xc contributions - e.g. like in VASP)

Thank you very much in advance!

Kind regards,

Vojtech

Hi,
from the comments of the code in stress.F90, where the stress is calculated:

!! NOTES
!! * Concerning the stress tensor:
!! See O. H. Nielsen and R. M. Martin, PRB 32, 3792 (1985).
!! Note that first term in equation (2) should have minus sign
!! (for kinetic energy contribution to stress tensor).
!! Normalizations in this code differ somewhat from those employed
!! by Nielsen and Martin.
!! For the stress tensor contribution from the nonlocal Kleinman-Bylander
!! separable pseudopotential, see D. M. Bylander, L. Kleinman, and
!! S. Lee, PRB 42, 1394 (1990).
!! Again normalization conventions differ somewhat.

Also, if you do your run with prtvol 10, all the contributions to the stress tensor will be output to the log file (not the main output file, just the log file).

Hope this helps--

Thanks a lot! It seems to be exactly what I was looking for.

Vojtech