Molcas Forum

mcurie747

Member

Registered: 2019-12-12

Posts: 21

Orbital Energy

Hi everyone, I was wondering if there is any way to obtain the orbital energies from a RASSCF calculation. Hope you guys can help me. Thanks

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: Orbital Energy

Print pseudo-canonical orbitals. Then you'd have energies but no occupations.

There's just no way around it: for multiconfigurational wavefuctions you can only have occupations or energies (or none), but not both.

valera

Administrator

Registered: 2015-11-03

Posts: 129

Re: Orbital Energy

mcurie747, oh, there are many ways. Let me show on example.
if you have two configurations, so resulting  wavefunction is a linear combination = c_1 \psi_1 + c_2 \psi_2. For each of individual configuration you can get orbital energies - for instance you can try to  make SCF for each configuration. With some efforts you can try to match the orbital energies between two calculations (which is already speculative, since in general they are different for different configurations). And the rest is fully speculative - how do you mix them? with weights as c_1, or c_1^2, or ?
In other words, if you want to introduce your own definition of orbital energies for multiconfigurational calculation - you can do it, but such construct, as I afraid, will have very little practical sense.

mcurie747

Member

Registered: 2019-12-12

Posts: 21

Re: Orbital Energy

Got it! Thank you very much both of you.