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Dear VASP Users,

I have noticed that the center-of-mass moves in the constant-pressure MD from snapshot to snapshot. As the volume of the cell changes shape, does the origin also move? In other words, what is the reference point for defining the coordinates of the particles?

Thanks,
Vahid

Dear Admin,

I am asking this question because when I run constant volume MD on N2 at 3000K and 35GPa, I get peaks in the VDOS that agree with published data. However, I do not get the same peaks when doing constant pressure MD! I get much broader, less defined and shifted-in-frequency peaks. So I suspect something is odd with the trajectory of the constant-pressure runs. This occurs even after I correct for the center-of-mass motion.


Vahid