error "geom input: too many centers? 3000"


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Hi all,

I'm new with NWChem and QM in general. I tried to submit an input file but I got the following error:



geom_input: too many centers?     3000
------------------------------------------------------------------------
There is an error related to the specified geometry
------------------------------------------------------------------------

I am trying to calculate the polarizability of a large (10,000 atom) polymer system, where the box is periodic in x,y, and z. To do this I made the following input file, where i excluded most of the coordinates for simplicity:

start s-p-1
geometry units angstrom
H   0.936693251173493       0.950015378158331       0.952596184574183
C 0.932171405659065 0.962180144737754 0.966930027939623
C 0.954733488603639 0.968188188709686 0.982964669074146
[extra coordinates]
system crystal
lat_a 45.35310
lat_b 45.35310
lat_c 45.35310
alpha 90.00000
beta 90.00000
gamma 90.00000
end
end
basis
H library 6-31g*
C library 6-31g*
end
dft
mult 1
XC pbe0
end
property
response 1 0
velocity
end
title "s-p-1 polariability calculation"
task dft property

Because the system is periodic, I wrapped the coordinates so that they are in the simulation cell and x, y, and z under the "geometry units angstrom" are in fractional coordinates.

Is there anything obviously wrong that causes the error: geom_input: too many centers?"

Thank you

Forum Vet
Tchantaw
Your calculations has exceeded the maxim number of atoms that the default NWChem source code
can deal with (3000).
You can either decrease the number of atoms in your input file or modify the maximum number of atoms in the NWChem source code and recompile.
For this second option, you need to do the following:
1) edit $NWCHEM_TOP/src/util/nwc_const.fh at the line
      parameter (nw_max_atom =3000)

2) recompile


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