# Re: CCL:Single point calculation in CRYSTAL03

*From*: Chimica Teorica <teoricach _+_ unito.it>
*Subject*: Re: CCL:Single point calculation in CRYSTAL03
*Date*: Tue, 07 Jun 2005 10:13:47 +0200

"Ojwang, J.G.O." wrote:
>
> Dear all,
> Is there anyone with an idea on how to perform single point calculation in
CRYSTAL03 without geometry optimisation of the internal coordinates, something
like freezing the atoms while expandinbg the lattice.
Dear Ojwang, J.G.O.,
the default choice of CRYSTAL03 is a single point calculation.
Optimization of internal coordinates is requested by the keyword
OPTCOORD
(the program checks if there are internals degrees of freedom).
See http://www.crystal.unito.it => tutorials => Total
energy single
point
You can modify the lattice parameters for each single point run,
keeping constant the internal (fractionary) coordinates of the atoms.
In case of molecular crystals, the keyword MOLEXP allows
modification of the lattice parameters, keeping constant the
internal coordinates and the fractionary coordinate of the
barycentre of each molecule.
Regards,
CRYSTAL support team Torino