My Community

Hi,

my understanding from the documentation is that IBRION=6 should be compatible with LEPSILON=.TRUE.; I'd like to use these features together as a simple way to compute the elasto-optic tensor by finite differences. However, when I combine them, the code runs and the elastic tensor is computed correctly but there is no LEPSILON-related output. I'm a bit new to VASP so not too sure at this point how to proceed. Any suggestions would be very welcome.

thanks,
Joe Zwanziger

Thank you for reporting the incompatibility. It will be corrected in the documentation.
LEPSILON=.TRUE. combines with IBRION=8.
When using IBRION=6 you can initialize the calculation of the dielectric tensor
using LCALCEPS=.TRUE.

Yes, LCALCEPS indeed gives a computation of the dielectric tensor for the original unstrained cell at the beginning of an IBRION=6 run, but does not appear to compute anything for each of the strained cells. Or am I missing something? Thanks--