title: Temperature Dependence of Electron Spin Relaxation of 2,2-diphenyl-1-picrylhydrazyl in Polystyrene.
abstract: The electron spin relaxation rates for the stable radical DPPH (2,2-diphenyl-1-picrylhydrazyl) doped into polystyrene were studied by inversion recovery and electron spin echo at X-band and Q-band between 20 and 295 K. At low concentration (340 μM, 0.01%) spin-lattice relaxation was dominated by the Raman process and a local mode. At high concentration (140 mM, 5%) relaxation is orders of magnitude faster than at the lower concentration, and 1/T1is approximately linearly dependent on temperature. Spin lattice relaxation rates are similar at X-band and Q-band. The temperature dependence of spin echo dephasing was faster at about 140 K than at higher or lower temperatures, which is attributed to a wagging motion of the phenyl groups.
authors.affiliation: Department of Chemistry and Biochemistry University of Denver, Denver, Colorado 80208.
authors.forename: Virginia
authors.initials: V
authors.lastname: Meyer
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Eaton
authors.forename: Gareth R
authors.initials: GR
authors.lastname: Eaton
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