Geometry optimization

Queries about input and output files, running specific calculations, etc.


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VitOldy

Geometry optimization

#1 Post by VitOldy » Wed Jan 17, 2007 6:45 am

Hi,
VASP does geometry optimization at zero temperature.
However, experimental measurements may be performed at more higher temperatures.
Is it possible to combine geometry optimization and molecular dynamics
to obtain lattice constants and atomic positions at, for example, T=300K ?
And if yes, how?
Last edited by VitOldy on Wed Jan 17, 2007 6:45 am, edited 1 time in total.

tjf
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Geometry optimization

#2 Post by tjf » Wed Jan 17, 2007 11:15 am

1) Run the MD for a suitable period of time.
2) Time-average the coordinates!

(For lattice constants, applying the quasiharmonic approximation---calculating phonon density of states and minimising the free energy---can also be applied. See PRB 73 (2006) 174302. But that approach is much harder.)
Last edited by tjf on Wed Jan 17, 2007 11:15 am, edited 1 time in total.

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