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Compatibility between IBRION=6 and LEPSILON

Posted: Thu Sep 01, 2016 7:50 pm
by jzwanzig
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

Re: Compatibility between IBRION=6 and LEPSILON

Posted: Mon Sep 12, 2016 11:37 am
by admin
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.

Re: Compatibility between IBRION=6 and LEPSILON

Posted: Thu Sep 15, 2016 5:09 pm
by jzwanzig
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--