The quantified NTO analysis for the electronic excitations of molecular many-body systems

► Physical origin of electronic excitations can be systematically investigated. ► TDDFT with LC hybrid functionals can produce physical origins similar as EOM-CCSD. ► Excitations assignment can be performed even when group theory is not applicable. ► Clear physical insights of excitations of complex biomolecules can be obtained. ► Transition origin variation due to environments can be studied.