Dear All,
I just want to calculate ground->excited oscillator strength. It seems both ground->excited and excited->excited transitions are calculated with input “property(‘eom-cc2’, properties=[‘oscillator_strength’])”. I am wondering if there is anyway to skip excited->excited calculations to save calculation time.
Thank you very much.
Best regard,
Michael
Unfortunately, the excited state->excited state transition properties are always computed when one requests an eom property calculation involving more than 1 state. But we can definitely add some boolean as an option to avoid these computations if they are not needed.
Thank you. I think this should be very useful, since with the number of states increasing, the number of excited->excited is much larger than that of ground->excited.
I should point out that the calculation of the excited state->excited state properties is essentially free in the formulation we’re using. The real cost of the computation is in obtaining the left- and right-hand excited-state wave functions, all of which are required for the ground state->excited state properties anyway. So removal of the excited state transition property calculation will not save you any significant time.
I see. Thank you very much!
btw, what’s the difference between the following two calculations?
property(‘eom-cc2’, properties=[‘dipole’])
property(‘eom-cc2’, properties=[‘oscillator_strength’])
I found both in example files. And it seems they produced same type of results, but in different convergence criteria.
The convergence criteria for the oscillator strengths (and rotatory strengths) have been loosened because we’ve found that we don’t need tight criteria for the left-hand wave functions for transition properties (in most cases). This is likely true also for excited-state dipole moments, but we just haven’t tested it, hence the different defaults.