Noise in LOCPOT

Problems running VASP: crashes, internal errors, "wrong" results.


Moderators: Global Moderator, Moderator

Post Reply
Message
Author
tlchan

Noise in LOCPOT

#1 Post by tlchan » Wed Dec 20, 2006 4:04 pm

For surface calculation, I found that LOCPOT has a lot of noise. If the surface is in the x-y plane, I pick an x and y on the surface and plot the potential along the z direction, I found that there are a lot of fluctuations when the potential is decaying into the vacuum. In addition, it seems like if I let VASP adding the exchange-correlation part into the local potential, the noise is even bigger. Is there any way to improve this situation? Thank you.
Last edited by tlchan on Wed Dec 20, 2006 4:04 pm, edited 1 time in total.

admin
Administrator
Administrator
Posts: 2921
Joined: Tue Aug 03, 2004 8:18 am
License Nr.: 458

Noise in LOCPOT

#2 Post by admin » Wed Dec 27, 2006 11:02 am

the XC part converges only slowly therefore it is omitted in LOCPOT if you run the default version of vasp.
concerning the fluctuations (without XC):
please check if
1) your calculations were really converged (basis set sizes, electronic and ionic ground state)
2) if the vacuum is thick enough to avoid spurious surface-surface interactions across the vacuum
Last edited by admin on Wed Dec 27, 2006 11:02 am, edited 1 time in total.

Post Reply