Dipole gradients not possible for high spin

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Dipole gradients not possible for high spin

Post by cymantren » 23 Jul 2020, 14:36

Hello DALTON users and developers,

I almost (happily and with some help) finished the optimizations on 2^B2 and wanted to compare this results with the 4^A2 state, but the program complains, that
"ERROR: Dipole gradients and molecular not implemented for high-spin restricted open-shell HF ".
This time I used the WALK-module which uses pure 2ndord-methods. Changing the inputs according to the manual, leads to no further improvements, and I want to ask:
a) how one can do an 2ndord optimization on a quartet state

b) how does one use the restart of e.g an optimization file.
in connection with the "SIRIUS.RST"-file did'nt work.

Thank you !

Kind regards

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Re: Dipole gradients not possible for high spin

Post by kennethruud » 23 Jul 2020, 22:24


Dalton does not have full support for ROHF wave functions in the different property modules, as you have now experienced. I note you have a fairly small molecule and quite high symmetry, so my recommendation would be to model the ROHF state through an MCSCF wave function with only the singly occupied orbitals in the CAS space. With this approach, you should also be able to do a second-order geometry optimization and calculate the dipole gradients.

As for restart, remember to remove possible .HF/.MP2 keywords from the input file, see Section 5.4 in the Dalton manual.


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