Molcas Forum

Sreenithya

Member

Registered: 2015-12-02

Posts: 8

Comparison of calculations

Is it correct to compare the calculations with same active space size but different orbitals?

niko

Member

From: Marseille

Registered: 2015-11-08

Posts: 61

Website

Re: Comparison of calculations

Yes, as long as the model remains consistent: same basis set, same active space, same level shift (if any), same frozen orbitals (if any) and so on ...

Sreenithya

Member

Registered: 2015-12-02

Posts: 8

Re: Comparison of calculations

Thank you Niko for your reply.

I guess 'same active space' implies size. Am I correct?

Actually I wanted to compare two calculations.
One active space involves a C-H bond whereas the other does not. But the size of active space remains the same.

niko

Member

From: Marseille

Registered: 2015-11-08

Posts: 61

Website

Re: Comparison of calculations

I guess 'same active space' implies size. Am I correct?

Actually I wanted to compare two calculations.
One active space involves a C-H bond whereas the other does not. But the size of active space remains the same.

Actually the size matters, but not only: the orbitals have to keep the same electronic character. In other words, if you want to describe a C-H bond, hence using the corresponding sigma and sigma* orbitals, you need to include them in all your calculations.

Sreenithya

Member

Registered: 2015-12-02

Posts: 8

Re: Comparison of calculations

Okay
Thanks for your kind reply