My Community

hi,
this topic has been discussed few times in the forum but for me it is not still clear how to use NOSE-HOVER dynamics apropriatly in the VASP.
i set the tempurature 300K in my system but it fluctuates between 0 and 2800K during the calculation. previously ADMIN recommmends to use SMASS=-1 and NBLOCK to control the tempurature that works nicely in my case to control tempurature BUT As stated in the forum (http://cms.mpi.univie.ac.at/vasp-forum/ ... php?4.1236) that is not really NOSE-HOVER dynamics.

the problem could be setting SMASS to a wrong number.
in my case i set SMASS=0 in al cases but change POTIM for few test calculations, since i dont know what it means SMASS>0

i will really apreciate some help to set the SMASS for following case.

for diamond Raman specrum gives a 1332 cm-1 peak, which correspond to a frequency of f=0.00632 /fs, and the period of that mode will be T= 158 fs.
what should i set for SMASS in this case if i use POTIM=0.5

thanks a lot for any comment.

we also want to perform MD calculation for stability analysis with keeping temperature constant (NVT). Is it appropriate to use SMASS = -1. is it possible to use SMASS > 0 without temperature fluctuations? (how does the temperatue fluctuations affect the calculations or results)