[Pw_forum] K_POINTS, tpiba or crystal

Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu
Mon Dec 29 20:20:07 CET 2008

On Mon, 29 Dec 2008, Paul M. Grant wrote:

hi paul,

PG> When specifying a user generated mesh for an nscf run, should tpiba (the
PG> default) or crystal coordinates be designated on the  K_POINTS card?

most likely tpiba.

PG> Frankly, I don't understand what "crystal" means wrt to reciprocal space
PG> (ATOMIC_POSITIONS, yes), and it does seem to make a small difference

in my understanding, crystal would be multiples of the 
reciprocal lattice vectors, i.e. the "b"-matrix printed
out at the beginning of a job.


PG> depending on the application (e.g. Fermi surface generation).

PG> A Merry Winter Solstice Break to All.
PG> Paul M. Grant, PhD
PG> Principal, W2AGZ Technologies
PG> Visiting Scholar, Applied Physics, Stanford (2005-2008)
PG> EPRI Science Fellow (Retired)
PG> IBM Research Staff Member Emeritus
PG> w2agz at pacbell.net
PG> http://www.w2agz.com <http://www.w2agz.com/> 

Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
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If you make something idiot-proof, the universe creates a better idiot.

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