Dear all, I would like to study MD with NPT ensemble. I am learning example 18 in QE 4.2.1 which uses cp.x to perform molecular dynamics simulation of SiO2.
For the vc-cp simulation, input file specify tempw=300 and press=1.0. However, the ? Averaged Physical Quantities ????????????????????? accomulated????? this run ?? ekinc???????? :??????? 0.00001?????? 0.00001 (AU) ?? ekin????????? :?????? 94.60238????? 94.60238 (AU) ?? epot????????? :???? -343.05127??? -343.05127 (AU) ?? total energy? :???? -211.98234??? -211.98234 (AU) ?? temperature?? :??????? 0.75835?????? 0.75835 (K ) ?? enthalpy????? :???? -211.93045??? -211.93045 (AU) ?? econs???????? :???? -211.93020??? -211.93020 (AU) ?? pressure????? :?????? -2.19645????? -2.19645 (Gpa) ?? volume??????? :???? 1526.61474??? 1526.61474 (AU) Why the averaged temperature and pressure in the output file are far? away from the target value set in the input? One more question, what is the purpose of using cp, cp-restart, vc-cp, and vc-cp-restart together? Is this a routine to study MD, i.e. combing these four? In other words, could we just get the vc-cp part for investigating NPT ensemble? Best regards Jingyun -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100802/8a44c467/attachment.htm
