Help with Choosing Quantum Numbers for MPSH Eigenstates

[Jahanzaib]

Hello Experts,
I followed the tutorial on molecular devices (https://docs.quantumatk.com/tutorials/molecular_device/molecular_device.html), but I am unclear about a few steps. Specifically:

When MPSH with atom indices (37, 38, 39, 40, 41, 42, 43, 44, 45, 46) is computed, I don't understand how or why quantum numbers 13, 14, 15, and 16 are chosen in the next step.

I have my own system, as shown in the attached pictures, and I am interested in observing the overlap between tin atoms 40, 92, and 95. I've calculated MPSH, but I am unsure how to choose the correct quantum numbers for eigenstate analysis?

[Anders Blom]

The selection in the screenshot is used to indicate where the Fermi level is - you can see that 14 is occupied and 15 not, so 14 is HOMO and 15 is LUMO. That makes these states interesting to investigate further, in this case at least.

[Jahanzaib]

Many thanks - I got the your point.