Input file for crystal in NWchem

Hello
Let me know how to build input file for frequency calculations of crystal
structure in NWchem.


Mohammad Jane Alam
Research Scholar
Physics Department
A.M.U. Aligarh

Let me know how to build input file for frequency calculations of crystal structure in NWchem.

I think the key word there is crystal structure. If you read in CIF or other crystallographic file formats, you can supply this to NWChem. Alternatively, you can get access to the development version of Avogadro (v1.1) with improved crystal features by downloading XtalOpt:

The newer version of Avogadro and XtalOpt allow you to enter atoms for a crystal in fractional coordinates, set the space group, etc.

Hope that helps,
-Geoff


Prof. Geoffrey Hutchison
Department of Chemistry
University of Pittsburgh
tel: (412) 648-0492
email: geoff.hutchison@gmail.com
web: http://hutchison.chem.pitt.edu/

On Thu, Mar 15, 2012 at 1:01 PM, Geoffrey Hutchison geoff.hutchison@gmail.com wrote:

Let me know how to build input file for frequency calculations of crystal
structure in NWchem.

Be careful here, too – for crystal structures, you generally want to
calculate the phonon structure across q-space to test for
saddle-points, determine finite temperature effects, etc – not
regular vibrational frequencies as with isolated molecules. I’m not
sure if NWChem will calculate phonons without additional software
(like PHON, phonopy, fropho, etc, which work with VASP – not sure
about other codes).

Dave

I think the key word there is crystal structure. If you read in CIF or other
crystallographic file formats, you can supply this to NWChem. Alternatively,
you can get access to the development version of Avogadro (v1.1) with
improved crystal features by downloading XtalOpt:

http://xtalopt.openmolecules.net/

The newer version of Avogadro and XtalOpt allow you to enter atoms for a
crystal in fractional coordinates, set the space group, etc.

Hope that helps,
-Geoff


Prof. Geoffrey Hutchison
Department of Chemistry
University of Pittsburgh
tel: (412) 648-0492
email: geoff.hutchison@gmail.com
web: http://hutchison.chem.pitt.edu/


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