Dear All,
I read all posts about this topic, how to identify HOMO & LUMO energy from MPSH energy spectrum . i read Dr Anders Blom about this topic in this link,
http://quantumwise.com/forum/index.php?topic=185.msg1050#msg1050 as dr anders say , by definition the HOMO has the highest negative energy and the LUMO the lowest positive energy.
What about HOMO-1 or LUMO+1
![Huh? ???](https://forum.quantumatk.com/Smileys/default/huh.gif)
My system have 40 shell electron which mean orbital no 20 is HOMO and orbital no 21 is LUMO when i calculate MPSH spectrum and project it on molecule only, i got results in the attached file.
Now i want to ask few questions
![Smiley :)](https://forum.quantumatk.com/Smileys/default/smiley.gif)
1- How to identify HOMO, HOMO-1, LUMO, LUMO+1 and so on
![Huh? ???](https://forum.quantumatk.com/Smileys/default/huh.gif)
2- what are this many values some are positive values (+) and the other are negative value (-)
![Huh? ???](https://forum.quantumatk.com/Smileys/default/huh.gif)
3- for my information i have 40 valence electron so i have only 40 values have of them for 20 occupied orbitals and the later half for 20 unoccupied orbitals, (Am right or not)
![Huh? ???](https://forum.quantumatk.com/Smileys/default/huh.gif)
waiting for your answer as soon as possible,
Thanks in Advance,
Khattab