Numerical Geometry Optimization for CCSD(T)

[mike]

Hi there,

As only CCSD(T) energies are available in TM, I'm wondering if it's possible to do a numerical optimization with CCSD(T), like it seems was done for MP2 in earlier versions of Turbomole. See: http://www.uni-koeln.de/themen/chemie/software/turbomole/DOK/html/node176.html

Does anyone already have such a code ?

Or is anyone familiar with the MP2OPT code mentioned in the above link ? Could it be easily modified to do numerical CCSD(T) optimizations ?

Many thanks,

Mike

[antti_karttunen]

Hi Mike,

At least in TM 6.5 the "scripts" directory includes a script called NumGrad. It prints out a short documentation with NumGrad -help. It seems that it can also be combined with jobex (jobex -level NumGrad). I did a quick test at HF level and it seems to work OK (runs without crashing, that is). I have no idea why it isn't mentioned in the manual, maybe because it's a rather new addition.

Best,
Antti

[uwe]

Hi Mike, Hi Antti,

numerical gradients which can also be used in combination with jobex for geometry optimizations will officially be supported in TM version 6.6. It does work already in 6.5 but the usage is a bit complicated - Antti was on the right track...

Regards,

Uwe

[Hauke]

This sounds interesting. Is there a reason why NumGrad is still not mentioned in the manual of TM 6.6?

[christof.haettig]

Because things needed to be cleaned up.