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Title: Higher triplet state of fullerene C{sub 70} revealed by electron spin relaxation

Spin-lattice relaxation times T{sub 1} of photoexcited triplets {sup 3}C{sub 70} in glassy decalin were obtained from electron spin echo inversion recovery dependences. In the range 30–100 K, the temperature dependence of T{sub 1} was fitted by the Arrhenius law with an activation energy of 172 cm{sup −1}. This indicates that the dominant relaxation process of {sup 3}C{sub 70} is described by an Orbach-Aminov mechanism involving the higher triplet state t{sub 2} which lies 172 cm{sup −1} above the lowest triplet state t{sub 1}. Chemical modification of C{sub 70} fullerene not only decreases the intrinsic triplet lifetime by about ten times but also increases T{sub 1} by several orders of magnitude. The reason for this is the presence of a low-lying excited triplet state in {sup 3}C{sub 70} and its absence in triplet C{sub 70} derivatives. The presence of the higher triplet state in C{sub 70} is in good agreement with the previous results from phosphorescence spectroscopy.
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, Institutskaya St. 3, 630090 Novosibirsk (Russian Federation)
  2. Berlin Joint EPR Lab, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)
  3. (Russian Federation)
Publication Date:
OSTI Identifier:
22493413
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 24; Other Information: (c) 2015 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; ACOUSTIC ESR; DECALIN; ELECTRONS; EMISSION SPECTROSCOPY; FULLERENES; LIFETIME; MODIFICATIONS; PHOSPHORESCENCE; SPIN; SPIN-LATTICE RELAXATION; TEMPERATURE DEPENDENCE; TRIPLETS