Exact Treatment of the Coupled Coherent and Incoherent Motion of Triplet Excitons and Its Influence on the Lineshape of ESR

✍ Scribed by P. Reineker

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 818 KB
• Volume: 52
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2220520213

✦ Synopsis

Abstract

The motion of excitons is considered by a stochastic model comprising both its coherent and incoherent motion. The coherent motion is determined by the exchange interaction integral J whereas the incoherent motion is described by the strengths of local (γ~0~) and non‐local (γ~1~) fluctuations. The spin motion is described by the usual spin Hamiltonian of two differently oriented molecules. The equation of motion of the density matrix of the system is solved and the lineshapes of ESR are calculated for several sets of the above parameters by computer calculation. Especially, it is shown that the coherent motion too may lead to a single absorption line as previously obtained for incoherent exciton motion. Furtheron, it is inferred that the transition from coherent to incoherent exciton motion is determined mainly by the ratio of γ~0~ and J and that γ~1~ is a decisive quantity in the transition from the broadening of one or several ESR lines to the narrowing of a single line.