Problems in charge calculations
Posted: Thu Mar 22, 2007 3:48 pm
Hi all,
After reading in the forum that the newest version has a fix for non-orthogonal unit cells, I downloaded the source code from cvs and compiled it on our local computer.
I'm using the .cube files generated from a dacapo netCDF file (as described in https://wiki.fysik.dtu.dk/ase/Analysis#bader-analysis). I start with a simple (111) slab of a transition metal (the PSP for which treats 10 valence electrons). When I execute 'bader TMslab.nc' I get the following charges for the surface TM atoms --
# X Y Z CHARGE MIN DIST
----------------------------------------------------------------
1 0.0000 0.0000 0.0075 8.7264 0.0075
2 2.6625 4.6115 0.0075 20.0584 1.2420
3 5.3249 9.2230 0.0075 1.3035 0.0484
So, as you see here, although the total number of electrons on the surface atoms is almost retained, the charges for the three identical surface atoms are different from each other by a LARGE margin.
I found an earlier post on the forum, where somebody was having the same problem for 2 H atoms in their setup (although the difference in the charges there was much smaller <0.1 e). They seemed to have solved the problem by increasing the FFT grid, but it doesn't help in my case, unfortunately.
Any clues? Am I doing something grossly wrong/overlooking some important aspect?
Thank you in advance,
Mane
After reading in the forum that the newest version has a fix for non-orthogonal unit cells, I downloaded the source code from cvs and compiled it on our local computer.
I'm using the .cube files generated from a dacapo netCDF file (as described in https://wiki.fysik.dtu.dk/ase/Analysis#bader-analysis). I start with a simple (111) slab of a transition metal (the PSP for which treats 10 valence electrons). When I execute 'bader TMslab.nc' I get the following charges for the surface TM atoms --
# X Y Z CHARGE MIN DIST
----------------------------------------------------------------
1 0.0000 0.0000 0.0075 8.7264 0.0075
2 2.6625 4.6115 0.0075 20.0584 1.2420
3 5.3249 9.2230 0.0075 1.3035 0.0484
So, as you see here, although the total number of electrons on the surface atoms is almost retained, the charges for the three identical surface atoms are different from each other by a LARGE margin.
I found an earlier post on the forum, where somebody was having the same problem for 2 H atoms in their setup (although the difference in the charges there was much smaller <0.1 e). They seemed to have solved the problem by increasing the FFT grid, but it doesn't help in my case, unfortunately.
Any clues? Am I doing something grossly wrong/overlooking some important aspect?
Thank you in advance,
Mane