IONIC contribution to dielectric tensor and NSW
Posted: Wed Dec 26, 2012 7:35 pm
The past couple of days I have been unable to calculate the IONIC contribution to the dielectric tensor within VASP. I could calculate the dielectric tensor with no problem, but just could never get the IONIC contribution.
The manual, wiki, and forum posts suggest to use IBRION=7 or IBRION=8, along with LEPSILON=.TRUE. However, what is not clear is that NSW should apparently be set to 1 in order for this calculation to proceed. Explicitly setting NSW=0 in the INCAR file, which I figured would make no difference since the documentation says that NSW=0 by default, will cause the IONIC contribution to not be calculated.
Thought I would mention this for others who are running into this as well since it took me a number of substitutions in my INCAR file to try to figure out what the offending flag was. Perhaps the documentation should note that 0 isn't the default for NSW in all cases.
<span class='smallblacktext'>[ Edited ]</span>
The manual, wiki, and forum posts suggest to use IBRION=7 or IBRION=8, along with LEPSILON=.TRUE. However, what is not clear is that NSW should apparently be set to 1 in order for this calculation to proceed. Explicitly setting NSW=0 in the INCAR file, which I figured would make no difference since the documentation says that NSW=0 by default, will cause the IONIC contribution to not be calculated.
Thought I would mention this for others who are running into this as well since it took me a number of substitutions in my INCAR file to try to figure out what the offending flag was. Perhaps the documentation should note that 0 isn't the default for NSW in all cases.
<span class='smallblacktext'>[ Edited ]</span>