Multiwfn forum / Excitation energies are less than frontier orbital energies

Re: Excitation energies are less than frontier orbital energies

dummy@example.com (sobereva) — Sun, 24 Jan 2021 13:42:04 +0000

Even if the excitation is only contributed by HOMO-LUMO transition, the excitation energy and HOMO-LUMO gap are still different, because they differ with each other by excition binding energy, see Section 2 of this post: http://bbs.keinsci.com/thread-16758-1-1.html

Excitation energies are less than frontier orbital energies

dummy@example.com (fyzan) — Sun, 24 Jan 2021 11:55:13 +0000

Dear sir, the excitation energies are much less than frontier orbitals energy difference. like for excited state 1 the excitation energy is 5.0615 eV in the example file of N-phenylpyrrole.out present in Multiwfn example/excit folder but its HOMO (38)-LUMO (39) energy gap is 7.754761768 eV. How to explain these results?