On the origin of the inverted singlet–triplet gap of the 5th generation light-emitting molecules
Lucie Tučková, Michal Straka, Rashid R. Valiev, Dage Sundholm
Abstract
levels show that the singlet-triplet gap is inverted as compared to the one expected from Hund's rule, whereas all density functionals yield the triplet state as the lowest excited state. Double excitations responsible for the inverted singlet-triplet gap have been identified. Employing the spin-flip and ΔSCF methods, singlet-triplet inversion was obtained at the density functional theory level for some of the studied molecules.
Topics & Concepts
Singlet stateTriplet stateDensity functional theorySinglet fissionExcited stateCoupled clusterAb initioExcitationMoleculeChemistryAb initio quantum chemistry methodsDiradicalMolecular physicsAtomic physicsPhysicsComputational chemistryQuantum mechanicsOrganic chemistryPhotochemistry and Electron Transfer StudiesOrganic Light-Emitting Diodes ResearchMolecular Junctions and Nanostructures