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Title: Diffusion affected magnetic field effect in exciplex fluorescence

The fluorescence of the exciplex, {sup 1}[D{sup +δ}A{sup −δ}], formed at contact of photoexcited acceptor {sup 1}A{sup *} with an electron donor {sup 1}D, is known to be very sensitive to an external magnetic field, reducing the spin conversion efficiency in the resulting geminate radical ion pair, {sup 1,3}[D{sup +}…A{sup −}]. The relative increase of the exciplex fluorescence in the highest magnetic field compared to the lowest one, known as the magnetic field effect, crucially depends on the viscosity of the solvent. This phenomenon first studied experimentally is at first reproduced here theoretically. The magnetic field effect is shown to vanish in both limits of high and low solvent diffusivity reaching a maximum in between. It is also very sensitive to the solvent dielectric constant and to the exciplex and radical-ion pair conversion rates.
Authors:
 [1] ;  [2]
  1. Weizmann Institute of Science, Rehovot 76100 (Israel)
  2. Volgograd State University, University Avenue, 100, Volgograd 400062 (Russian Federation)
Publication Date:
OSTI Identifier:
22308778
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BINDING ENERGY; COMPARATIVE EVALUATIONS; DIFFUSION; EFFICIENCY; ELECTRONS; FLUORESCENCE; ION PAIRS; MAGNETIC FIELDS; PERMITTIVITY; RADICALS; SOLVENTS; SPIN; VALENCE