Molcas Forum

Joachim

Member

Registered: 2025-04-04

Posts: 2

Molcas tutorial 5.1.5.1.3

Hi everyone, this is my first time posting on this forum. Let me know if there are any good practices I should apply in future posts.
I struggle with the following:

1. Wave Function Printout (p. 617)
How can I obtain the wave function printout as shown on page 617? I checked the molcas_runex.log output file but couldn’t find it. Is there a specific keyword or setting needed to enable this printout?

2. Understanding State Classification (p. 618, Section 5.1.5.1.3)
The manual states that root 2 has a main configuration described by an excitation 3b₁ → 4b₁.

2a. Given the occupation numbers (1.4570 and 0.4122), I understand this is more likely than other options due to a good donor-acceptor pairing. Could someone confirm if this interpretation is correct?

2b. How do we determine that this corresponds to root 2 and not root 3?

2c. Additionally, the text states that 4b₁ is a valence orbital, making the resulting state a valence state. However, earlier on the same page, the fourth orbital is referred to as a Rydberg state.

I assumed "fourth" referred to the third excitation, with 4b₁ corresponding to the b₁ irrep of the third excited state. Did I misinterpret this labeling?

3. Orbital Identification
How is the 3b₁ orbital identified as HOMO−1? I found the 0.21 value in the image on p. 617, but I’m struggling to interpret its meaning.

Joachim

Member

Registered: 2025-04-04

Posts: 2

Re: Molcas tutorial 5.1.5.1.3

A link to the pdf can be found here:
https://molcas.gitlab.io/OpenMolcas/Man … #page=9.16