Using Hessproc

[Oscar N. Ventura]

Dear fellow users,

I am trying to optimize the geometry of a TS at the CCSD(T)-F12/VDZ-F12 level and I want to use a MP2 Hessian, which is faster to calculate (obviously).

I am attaching my input file and the log file (also the output, but it is not relevant). Unless I am not understanding it completely, it seems that the program is calculated the displacemenst using CCSD(T)-F12 and not the MP2 procedure I defined with the hessproc procedure. Am I wrong? If not, any suggestion of what may be the error?

FYI, I am using Molpro version 2020.1

Thanks for any tips.

Oscar

[Hans-Joachim Werner]

Dear Oscar,

it should read
{optg, root=2,hessproc=runmp2}

Option have to be given on the command line.

I have not tested this but hope it helps!
Joachim

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> <TS2B_CCSDTF12_VDZF12.out><TS2B_CCSDTF12_VDZF12.inp><TS2B_CCSDTF12_VDZF12.log>

[Oscar N. Ventura]

Dear Joachim:

Thank you for the answer.

Regretfully, I obtained the same result, for some reason it is ignoring the procedure and just calculating CCSD(T)-F12 :(

Regards.

[Oscar N. Ventura]

Just to give more context.

I tried the procedure with my older 2012.1 version and it works as intended.

It seems not to work in version 2020.1

Regards

[Hans-Joachim Werner]

Dear Oscar,
I have tried it with our current version (2021.3) and it looks fine. It first computes a numerical gradient for UCCSD(T)-F12. Look in the log file(s) for

Running default procedure: HF-SCF000 UCCSD(T)-F12

After that it computes the MP2 hessian using analytical gradients:

Running procedure: RUNMP2

It has finished the optimization but is still in frequencies

All 15 tasks completed. CPU= 78.38 sec, Elapsed= 79.23 sec.

MP2 hessian saved to record 5300.2

Entering Rational Function Geometry Optimization

ITER. ENERGY(OLD) ENERGY(NEW) DE GRADMAX GRADNORM GRADRMS STEPMAX STEPLEN STEPRMS CPU-time
1 -625.16511388 -625.16526257 -0.00014868 0.01949302 0.02468973 0.00164598 0.02491720 0.04325907 0.01635039 4961.49

MP2 hessian read from record 5300.2
2 -625.16526257 -625.16527866 -0.00001609 0.00155262 0.00289543 0.00019303 0.00942301 0.01318045 0.00498174 9627.80

MP2 hessian read from record 5300.2
3 -625.16527866 -625.16527896 -0.00000030 0.00061473 0.00104564 0.00006971 0.00246245 0.00417125 0.00157658 14300.28

MP2 hessian read from record 5300.2
4 -625.16527896 -625.16527896 -0.00000001 0.00015181 0.00022080 0.00001472 0.00164148 0.00211642 0.00079993 18976.98

END OF GEOMETRY OPTIMIZATION.

I can send you the output when it has finished.

I have not tried, but I doubt that this has changed since 2020.1. In any case, I recommend to update the program regularly to get all bug fixes.

Best wishes
Joachim
---
Prof. Dr. Hans-Joachim Werner
Institut für Theoretische Chemie
Universität Stuttgart
Pfaffenwaldring 55
70569 Stuttgart, Germany
e-mail: wer...@theochem.uni-stuttgart.de

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[Oscar N. Ventura]

Dear Joachim:

Thank you very much for your comments and help.

It has been very useful.

Best regards,

Oscar