[Pw_forum] Very large value of temperature at the beginning of a nose thrmostat run

[Lawrence Lee]

Dear all,

I am a newbie in using cp.x of the espresso package. I have a some problems concerning the use of nose thermostat in temperature control.

First I do an electronic and ionic minimization on my system. And finally the output file said convergence has been achieved. Then I restart from this to make a 3000K run.

Problem then emerge: when I looked at the cp.evp file, I found that the temperature has been so much higher than 3000K at some steps near the beginning (~0.079 ps to 0.089 ps, ie, 272 to 307 steps as I use dt =12), so high that the value is ****** (>10000K). However, after some 0.5 ps, the value stabilized, and fluctuating about 3000K with amplitude about a few hundred K. 

Other quantites after that about 0.5 ps all look fine, but that intermediate steps with very high temperature worries me. In fact, does it matter?

Lawrence Lee Shun Hang
MPhil student of the Chinese University of Hong Kong
tel: 852-61094093

       
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