Dear Paulo,

thanks for your mail. Maybe my question was not clear:
Fixing atoms in cartesian space is no problem (as in your example).
Fixing a dihedral in a Z-matrix should also be no problem. But I want to
do both at once for different atoms in my molecule (given preferably in
cartesian coordinates).

Is there a way to do this?

Timm

Paulo Jorge Costa wrote:

> Hello
>
> I think you can do it like this:
> (in this example the oxygen cartesian coordinates are fixed)
>
> (...)
> ATOMS
> O x1 y1 z1
> H 1.0 1.0 1.0
> H -1.0 1.5 2.3
> O x2 y2 z2
> H 0.1 1.2 1.01
> end
> (...)
> GEOVAR
> x1=1.02 F
> y1=1.03 F
> z1=1.04 F
> x2=1.05 F
> y2=1.06 F
> z2=1.003 F
> END
> (...)
>
> I hope this will help you
>
>
> **************************************************************
> Paulo Jorge Costa
> ITQB - Intituto de Tecnologia Química e Biológica
> Química Inorgânica e Teórica
> Oeiras - Portugal
> +351 214469769
> pjcosta_at_portugalmail.pt
> **************************************************************
>
>
>
>
> Timm Essigke wrote:
>
>> Dear all,
>>
>> I would like to run a geometry optimization of a fairly large
>> molecule. I need to fix certain atoms in cartesian space, on the
>> other hand I would like to constrain a dihedral. Is there a way to do
>> this?
>>
>> I thought about using ZCart, but it is stated that it can not be used
>> with constraints.
>>
>> Any hints are welcome!
>>
>> Timm
>
>
>
>
>
Received on 2003-02-26 17:22:12