[Pw_forum] Point Charges for Molecular Dynamics

[Giovanni La Penna]

Some hints for interacting molecules are in:

http://qe-forge.org/pipermail/pw_forum/2010-December/093283.html

The old RESP code is freely available in:

http://www.ccl.net/cca/software/SOURCES/FORTRAN/resp/

PP should run with plot_num=11, but the interpolation
of V values on the molecular surface or on the desired
subset of points must be done manually.
The selection of this points is the crucial step.
For Zn, Cu and Fe bound in coordination compounds
the recipe A gives results consistent with the (Gaussian Inc)
literature.

               Giovanni

============================================================
Giovanni La Penna - National research council (Cnr)
Institute for chemistry of organo-metallic compounds (Iccom)
via Madonna del Piano 10,
I-50019 Sesto Fiorentino, Firenze, Italy
tel.: +39 055 522-5264, fax: +39 055 522-5203
e-mail: glapenna at iccom.cnr.it - http://www.iccom.cnr.it/lapenna
============================================================

On Sun, 10 Aug 2014, Kevin Schmidt wrote:

> Hello PWSCF Forum,
> First time caller, long time listener.  I am working with a group using
> Quantum Espresso to extract two-body interatomic potentials (IP) for an
> ionic crystal system (metal borides, to be exact).  These potentials will
> then be put to use in molecular dynamics software (DL-Poly).  From my
> understanding with MD, most software nowadays typically employs
> electrostatics as a separate potential from the heteronuclear IP's.  In
> order to (1) get the correct heteronuclear IP and (2) simulate a "realistic"
> electrostatic environment in MD, it would be best to have the right point
> charges for the system.  After browsing through the forum and user guides, I
> noticed that PP.x (plot_num = 0) has the ability to output charge density
> distributions.  The output I received had, depending on which plot type
> used, five or six columns, of which I am assuming are related to charge
> values on a grid.  Is this correct, and if so, how do I find the
> corresponding grid?  
>