Geometry optimization with constraint that keeps same value for two bond lengths

[evgeniy]

Dear Developers and Users of TM,

I am wondering if it is possible to do geometry optimization
with the constraint that keeps the same value for
let's say two (ore more) bond lengths (or angles), even when
those internal coordinates are not symmetric (of course that
value is also optimized). Many thanks!

Best regards,
Evgeniy

[ardie]

I have the same question. No reply? Where is the TM support?

[uwe]

Hi,

the Turbomole support is here: turbomole@cosmologic.de
Feel free to contact the support team if you have questions about the program. This here is the Turbomole Users Forum, meaning that it was intended to offer a platform where users can share their experience with the program, and some developers do also read the posts here. But support is done by COSMOlogic and their resellers.

To the question:

I personally do not know how to do this with the default tools relax and statpt in Turbomole. But I know that a couple of users utilize other tools for geometry changes and only the energy and gradient modules of Turbomole. BOptimize from Peter Budzelaar, DL-find from Johannes Kästner, Baker's OPTIMIZE package come to my mind, but I am sure that there are more. You would have to check if one of them is able to do such constraints, this is not really a common application.

It might be easier to fix both lengths or angles at the same time with the same value and do a scan job like this.

Regards,

Uwe