interatomic potentials

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


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brsahu
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Joined: Tue Jun 14, 2005 6:21 pm
License Nr.: 68
Location: University of Texas at Austin

interatomic potentials

#1 Post by brsahu » Tue Aug 30, 2005 8:40 pm

Dear Vaspusers,

Using LVTOT tag one can get (in the file LOCPOT) the total electrostatic potential in a unit cell or electrostatic+exchg.corrleation potential in the unit cell.

The description of LVTOT tag in the manual says LOCTOT file
also contains average electrostatic potential 'at each ion' and can
calculate, I guess, avg. electrostatic+exchg.correlation potential
'at each ion'.

I have a supercell system with only one impurity atom.
I am interested in knowing the interatomic potential between
this impurity atom and a host atom. Say one Mn impurity in Ge
so I am looking for interatomic potential between this impurity
atom and a Ge atom in the host.

Can the avg potential (from LOCPOT file) at the impurity atom
be taken as the interatomic potential (between the impurity atom and a host atom)?

Can anyone explain how this avg potential at the ion site is calculated in vasp? Manual says (the first equation in LVTOT tag description) it is calculated by putting one test charge with norm 1. But I can not figure out why we have to put a test charge on
the ion site to calculate the avg. potential.

sahu
Last edited by brsahu on Tue Aug 30, 2005 8:40 pm, edited 1 time in total.
Dr. Bhagawan Sahu
Research Associate
Mircroelectronics Research Center
Univerisity of Texas at Austin
10100, Burnet Road, Bldg 160
Austin TX 78758, USA

brsahu
Newbie
Newbie
Posts: 18
Joined: Tue Jun 14, 2005 6:21 pm
License Nr.: 68
Location: University of Texas at Austin

interatomic potentials

#2 Post by brsahu » Tue Sep 06, 2005 8:03 pm

Dear Vasp users,

Do any users have suggestions to the above query?

sahu
Last edited by brsahu on Tue Sep 06, 2005 8:03 pm, edited 1 time in total.
Dr. Bhagawan Sahu
Research Associate
Mircroelectronics Research Center
Univerisity of Texas at Austin
10100, Burnet Road, Bldg 160
Austin TX 78758, USA

konglt

interatomic potentials

#3 Post by konglt » Wed Sep 07, 2005 4:44 pm

I guess you misunderstand the meaning of electrostatic potential, which means the potential felt by an electron in the field of ions (or atoms). It has nothing to do with the interatomic potential.

The obtained LOCPOT file can be used to get the work function of a specific surface by using a supercell.

LT
Last edited by konglt on Wed Sep 07, 2005 4:44 pm, edited 1 time in total.

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