[molpro-user] Help with SLAPAF Program

[Alexander Mitrushchenkov]

Dear Angelo,

I checked that constraints for SLAPAF are perfectly working for Molpro version 
2006.1, as described in the manual, section 43.3.1. I did not quite 
understand what you really want to do, so I attach two examples (with 
outputs) for propadiene. In the first one, each of two C=C bonds is 
constrained to a fixed value (which is different from initial bond length), 
while in the second the C=C bonds are kept equal but relaxed (for initial 
geometry they are different). Please let me know if this answers your 
question.

Best wishes,

Sasha

On Wednesday 30 January 2008 04:41, you wrote:
> Hello Everyone:
>
> Would you be able to provide me with a sample input file for the SLAPAF
> program which incorporates the PRIMITIVE and CONSTRAINT commands.
>
> I cannot get much of anything to work in this module of Molpro.
>
> I would like to perform a relaxed potential energy surface in which two
> opposite bonds of a molecule are fixed (constrained) but gradually
> stretched in small increments and the remaining degrees of freedom are
> optimized.
>
> I thought this would be an excellent application for the SLAPAF module, but
> it really hasn't turned out that way.
>
> I tried using a Z-matrix approach and then restraining one of the internal
> coordinates, but the Z-matrix isn't optimal when the molecule is stretched
> and the ends begin to rotate.  I want the freedom that the SLAPAF could
> potentially provide.
>
> I really appreciate your guidance and advice.  Thank you.
>
> Kind regards,
>
> Angelo

-----------------------------------------
Dr. Alexander Mitrushchenkov, IGR
Université Paris-Est
Laboratoire de Chimie Théorique, EA2180
5 bd Descartes, Champs-sur-Marne,
77454 Marne la Vallée Cedex 2 France

Phone:    +33(0)160957316
Fax:      +33(0)160957320
e-mail:   Alexander.Mitrushchenkov at univ-mlv.fr
-----------------------------------------
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*** Propadiene SLAPAF test

basis=vdz

geometry={x,y;
 c1;
 c2,,,,2;
 c3,,,,-2;
 h1,,1.4,,3.4;
 h2,,-1.4,,3.4;
 h3,,,1.4,-3.4;
 h4,,,-1.4,-3.4;
}


rcc=2.2;

hf;

{optg,method=slrf
 constraint,$rcc,bond,atoms=[c1,c2]
 constraint,$rcc,bond,atoms=[c1,c3]}
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*** Propadiene SLAPAF test

basis=vdz

geometry={x,y;
 c1;
 c2,,,,2.4;
 c3,,,,-2;
 h1,,1.4,,3.4;
 h2,,-1.4,,3.4;
 h3,,,1.4,-3.4;
 h4,,,-1.4,-3.4;
}


rcc=2.2;

hf;

{optg,method=slrf
 constraint,0,bond,atoms=[c1,c2],-1,bond,atoms=[c1,c3]}
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