QM/MM calculation with a charge qm region


Just Got Here
Hi,

I want to perform a qmmm optimization with nwchem 6.1. First I prepare my system that come from amber with this script.

The system is completely uncharged.

start test
prepare
source complex.pdb
new_top new_seq
new_rst
solvent name WAT model spce
modify segment 1 quantum
update lists
ignore
write test_ref.pdb
write test_ref.rst
end
task prepare


I have put the resid 1 as quantum, this resid is charged (-1)

How I put the charge for the qm region in the following script qmmm.nw and is it mandatory to give the charge for the qm region or not.



permanent_dir ./perm
scratch_dir ./data
start test

md
msa 200000
system test_ref
end
basis
* library 6-31++g  
end

dft
xc b3lyp
end

qmmm
region all
maxiter 100 3000
ncycles 5
density espfit
xyz foo
end

task qmmm dft optimize

Thx very much

Clicked A Few Times
You just add

charge -1

somewhere in the beginning of your input file

Clicked A Few Times
Thanks, this suggestion also works for me.

Jingbo


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