Spin—lattice relaxation of a nitroxide radical in a single crystal

✍ Scribed by E. Wajnberg; A. Alonso; O.R. Nascimento; M. Tabak

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 663 KB
• Volume: 199
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)80056-h

✦ Synopsis

Spin-lattice relaxation time, T, of tan01 (protonated and deuterated), in crystal matrix of &hydroxy-2,2,6,6-tetramethylpiperidine has been studied in the range IO-300 K. Continuous saturation technique was applied to inhomogeneous broadened ESR signals. For tanol-p a transition was observed at 133 K due to the freezing of methyl rotations: line broadening was observed in yand x-axis directions. T : ' was fitted to either of two expressions AT"+ C and B exp( d/M) +D. At 20 K the main contribution is due to a constant term (cross-relaxation effect) and is the same for both radicals. Above 100 K the effect of temperaturedependent terms became predominant. Fitting of data does not permit to make a clear choice between the T" and exponential models.