Coulomb subtraction

GULP
1

Hi Prof Gale,

I want to find pe of 2d slab of Ag with co2 on it, however, when I use the keyword molecule, I get an error. How do I rectify this?

molecule c6 kcal prt_two

name t0
scell
11.738000 10.165400 90.000000 0 0 0
sfractional
Ag core 0.87500 0.75000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.62500 0.75000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.75000 0.50000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.87500 0.25000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.37500 0.75000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.50000 0.50000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.62500 0.25000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.75000 0.00000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.12500 0.75000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.25000 0.50000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.37500 0.25000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.50000 0.00000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.00000 0.50000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.12500 0.25000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.25000 0.00000 7.18801 0.000000 1.000000 0.000000 0 0 0
Ag core 0.00000 0.00000 7.18801 0.000000 1.000000 0.000000 0 0 0
O core 0.47555 0.42704 10.76416 -0.350000 1.000000 0.000000 0 0 0
O core 0.47555 0.19881 10.76416 -0.350000 1.000000 0.000000 0 0 0
C core 0.47555 0.31292 10.76416 0.700000 1.000000 0.000000 0 0 0

lennard epsilon zero x13 kcal
Ag core Ag core 5.290000 2.629 0.0 15.0 0 0
O core O core 0.156990 3.050 0.0 15.0 0 0
C core C core 0.053655 2.800 0.0 15.0 0 0
C core O core 0.091779 2.925 0.0 15.0 0 0
Ag core O core 0.911305 2.8395 0.0 15.0 0 0
Ag core C core 0.532761 2.7145 0.0 15.0 0 0

Error: Coulomb subtraction within periodic molecules is not allowed

2

The error is because Ag is bonded to CO2 and so you have an infinitely large molecule. You need to either put the covalent radius of Ag to zero or exclude Ag-Ag and Ag-C/O bonds so that only CO2 is a molecule. If you only have one CO2 then just don’t put any charges since they won’t make any difference anyway.

3

Yes, the problem was solved. Thank you.