[CP2K-user] q-TIP4P/F

[may...@gmail.com]

Hi,

Sorry for continuing the chain, but is there an example for a flexible 
4-point classical force field implementation in a cp2k input file?

Best Regards,
Mayank Dodia

On Thursday, February 26, 2015 at 3:05:30 PM UTC+1 dan... at gmail.com 
wrote:

> I am trying to implement q-TIP4P/F (a flexible, 4-point water model: J. 
> Chem. Phys. 131, 024501 (2009)) into cp2k using the VIRTUAL_SITE module to 
> keep the negative charge in place. I was able to implement TIP4P (a rigid 
> model) without any problem, but I get the following error when I try to use 
> q-TIP4P/F:
>
> ********************************************************* 
> *** ERROR in get_molecule (MODULE molecule_types_new) *** 
> ********************************************************* 
>
> *** The pointer lci is not associated *** 
>
> I assume this is because VIRTUAL_SITE only works with constrained 
> molecules. If so, is there another way to constrain the negative charge for 
> a flexible 4-point model? 
>
> I’ve inserted the key areas of my input file for TIP4P (which works) and 
> q-TIP4P/F (which doesn’t work) below. I’ve also attached a full input file. 
>
> Thanks, 
>
> -- 
> Daniel Sadowsky 
> Ecole Polytechnique Fédérale de Lausanne 
> Environmental Chemistry Modeling Laboratory 
>
>
> @IF ( ${MD_FF} == TIP4P ) 
> &CONSTRAINT 
> SHAKE_TOLERANCE 1.0E-12 
> &G3X3 
> MOLECULE 2 
> ATOMS 1 2 3 
> DISTANCES [angstrom] 0.95720 0.95720 1.51390 
> &END G3X3 
> &VIRTUAL_SITE 
> INTERMOLECULAR FALSE 
> ATOMS 4 2 1 3 
> PARAMETERS 0.128012065 0.128012065 
> MOLECULE 2 
> &END VIRTUAL_SITE 
> &END CONSTRAINT 
> @ENDIF 
>
> @IF ( ${MD_FF} == QTIP4PF ) 
> &CONSTRAINT 
> SHAKE_TOLERANCE 1.0E-12 
> &G3X3 
> MOLECULE 2 
> ATOMS 1 2 3 
> DISTANCES [angstrom] 0.95720 0.95720 1.51390 
> &END G3X3 
> &VIRTUAL_SITE 
> INTERMOLECULAR FALSE 
> ATOMS 4 2 1 3 
> PARAMETERS 0.131940 0.131940 
> MOLECULE 2 
> &END VIRTUAL_SITE 
> &END CONSTRAINT 
> @ENDIF 
>
> @IF ( ${MD_FF} == QTIP4PF ) 
> &BOND 
> ATOMS Ow Hw 
> KIND QUARTIC 
> K 0.541925 -0.983779 0.926020 
> R0 [angstrom] 0.9419 
> &END BOND 
> &BEND 
> ATOMS Hw Ow Hw 
> KIND HARMONIC 
> K 0.139998 
> THETA0 [deg] 107.40 
> &END BEND 
> @ENDIF
>
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