values in LOCPOT file

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rgc · #1 Post by **rgc** » Mon Feb 16, 2009 3:26 pm

1- Are the values in the LOCPOT file multiplied by the volume of the cell, like in CHGCAR?

2- Are all the values multiplied by -1, with respect to the usual definition of the electrostatic potential? I think they are, but could anyone confirm this?

3- Are the two blocks printed always identical? (in CHGCAR, the two blocks are for the charge and for the spin density. In LOCPOT only one is necessary but two are printed...)

Thanks!

yuxiao_zihan · #2 Post by **yuxiao_zihan** » Tue Feb 17, 2009 8:49 am

As I understand, in LOCPOT, all the values is electrostatic potential. You do not need to multiply by the volume or -1. This is what I did for work function.

rgc · #3 Post by **rgc** » Tue Feb 17, 2009 1:24 pm

Thanks, Yuxiao. But I think that if you compare the Fermi energy with the values in LOCPOT, that actually means that these values are energies, not potentials, that is:

E=e*Pot=-1*Pot

where e=-1 is the electron charge. Don't you think?

I guessed that the potential was multiplied by -1 because I calculated the electrostatic potential above a surface, and the values in LOCPOT are more positive around the negative ions, and less positive around the cations. The opposite is expected...

yuxiao_zihan · #4 Post by **yuxiao_zihan** » Tue Feb 17, 2009 2:38 pm

If you calculate the surface, have you tried to get the vacuum level above the surface? Compared to Fermi energy, maybe you could find that it is potential.