Well, a couple of things here. Having a Ga and As separated by 5 angstroms is creating some of your problems, try a more realistic bond length like 2.0, i.e.
geometry units angstroms
Ga 0.0 0.0 -1.0
As 0.0 0.0 1.0
end
You will need to increase the number of iterations:
dft; iterations 300; direct; end
Also, I hope you're going to use a reasonable basis set and not the minimal sto-3g.
You hinted at the calculation not being able to find a basis set. If this is another issue, you should set NWCHEM_BASIS_LIBRARY to point to the location where the NWChem basis sets are on your machine (if you build from source it will be in <nwchem-path>/src/basis/libraries)
setenv NWCHEM_BASIS_LIBRARY <nwchem-path>/src/basis/libraries/
Hope this helps,
Bert
Quote: Jun 2nd 9:19 amHi Bert,
My trial input looks like:
Jun 2nd 9:19 am Local TimeJun 2nd 9:19 am Local TimeJun 2nd 9:19 am Local TimeJun 2nd 9:19 am Local TimeJun 2nd 9:19 am Local TimeJun 2nd 9:19 am Local Time~
title "GaAs"
geometry units angstroms
Ga 0.0 0.0 -2.5
As 0.0 0.0 2.5
end
basis
Ga library sto-3g
As library sto-3g
end
dft; direct; end
task dft optimize
The goal is to optimize accurately the GaAs structure (using quality DFT functional). Either PW or Gaussian (any would do,
or as required by accuracy goal). |