My Community

Dear All,

I think the problem is discussed already, but i couldn't find a specific solution.

I am working with the molecule on surface. But when analyzing the electronic structure, i find that the HOMO and the next lying level are fractionally occupied as below.

band 628 # energy -3.39666586 # occ. 2.00880383
band 629 # energy -3.09674157 # occ. 1.90015193
band 630 # energy -3.02750989 # occ. 1.52173790
band 631 # energy -2.90860550 # occ. 0.56437425
band 632 # energy -1.90758584 # occ. 0.00000000

Can someone guide me, which orbital should i consider a HOMO. I can find from E-fermi that 630 is HOMO and 631 is LUMO. Can the partial occupancy be allowed on LUMO.

Any detailed / short explanation would be helpful.
i tried with different values for Ismear tags and still have the same problem.

KMK

No replies yet.. Does everyone has the same problem. If so please suggest how to interpret these values.

kmkumar,
The terms "HOMO" and "LUMO" are not meaningful in systems with fractionally occupied orbitals. If you have fractionally occupied orbitals at the Fermi level (and assuming your calculation is correct), then your system is metallic. There is no HOMO or LUMO. Or put another way, the HOMO and LUMO are equal to each other, and both equal to the Fermi level.