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.

1 Like

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.

1 Like

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.

1 Like