ADC(2) NTOs

Dear All,
i am doing ADC(2) calculations on small organic molecules. Is there a way to get NTOs from the ADC(2) calculations or show the contributions of occupied and virtual orbitals for an excitation? I would like to characterise the electronic states before optimising them.

Best wishes and thank you in advance
Phillip

Dear Phillip,

if you perform canonical calculations, the "tprint" keyword controls the printing threshold of the coefficients (please, see in the manual). The canonical orbitals can be visualized using the generated MOLDEN file with the molden or jmol packages.

If you are interested in the reduced cost approximations using natural orbitals (please, see the redcost_exc keyword in the manual), in this case the natural orbitals unfortunately can not be obtained for visualization in the release version.

Please note that a more efficient ADC(2) solver will be soon available in the next release.

Thank you for using our program, if you have any further questions, please do not hesitate to ask.

Best wishes,

David

Dear David,
thank you very much for your help. Indeed i was doing reduced cost ADC(2). tprint was, what i was missing. Doing ADC(2) in the basis of the MOs, solves my problem for now.

May i ask if there are plans for the future, that would also allow the visualisation of the NOs? Or can the NOs be obtained from one of the other output files in some way?

Thank you again. MRCC is a very nice software!

Best wishes
Phillip

Dear Phillip,

your request has been implemented and will be soon available in the next release
If you will perform a reduced cost calculation with that forthcoming version, please, set the molden=on and verbosity=3 keywords in your MINP file. Thereafter the corresponding MOLDEN_NO.# files will be generated automatically, where # refers to the excited states. Since the natural orbitals are state-dependent, you should find as many files as the targeted excited states.

Some additional notes:
1. The files are generated and labelled via # in the order of the CIS excitation energies. The ADC(2) and CIS roots can be swapped. You can check if such rearrangement occured at the end of the output in the summary.

2. The natural orbitals are obtained from a so-called state-averaged [(MP2+CIS(D))/2] density matrix and then are pseudo-canonicalized before written to the MOLDEN_NO.# files. The energy values in the MOLDEN files refer to the corresponding pseudo-canonical orbital energies. You can find more details in the original paper: Journal of Chemical Physics, 148, p. 094111, 2018.

Best wishes,

David