Universal relationship between optical emission and absorption of complex systems: An alternative approach

Abstract

Analyses based on the theories of Kennard and of Stepanov (KS) often claim to support an assumption that emitting manifolds associated with excited electronic states are in thermal equilibrium. KS predict a certain linear F(ν) with slope -h/${\mathit{k}}_{\mathit{BT}}$, where T is ambient temperature. Variation in T*(ν)=-(h/${\mathit{k}}_{\mathit{B}}$)/(dF/dν) reveals the likelihood of extensive excited-state nonequilibration. T*(ν), not necessarily an actual temperature, reduces to T under fast relaxation. Its observed variation in certain systems can be modeled with coupled submanifolds far from the equilibrium envisaged by KS. © 1996 The American Physical Society.