Impact of molecular size on electron spin relaxation rates of nitroxyl radicals in glassy solvents between 100 and 300 K
Sato, Hiedo, Kathirvelu, Velavan, Fielding, Alistair, Blinco, James P., Micallef, Aaron, Bottle, Steven E., Eaton, Sandra S. , & Eaton, Gareth R. (2007) Impact of molecular size on electron spin relaxation rates of nitroxyl radicals in glassy solvents between 100 and 300 K. Molecular Physics, 105(15-16), pp. 2137-2151.
Electron spin lattice relaxation rates were measured for 12 nitroxyls with molecular weights between 144 and 438, and for galvinoxyl, 1,3-bisdiphenylene-2-phenylallyl (BDPA), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in glassy sucrose octaacetate. Relaxation rates for polar nitroxyls also were measured in glassy sorbitol. Dependence on T where Veff is effective molecular volume and γ is a material-specific parameter, was used to compare processes. Values of Veff were determined based on molecular libration in glassy sucrose octaacetate (γ = 3.5), tumbling in viscous decalin at 233 K (γ = 4.7), or tumbling in heavy mineral oil (γ = 6.0). For nitroxyl relaxation there is a master curve: log(1/T1) vs log( T) (γ = 0.89). The similarity of the values of γ for the Raman process and for the additional process that contributes at higher temperatures, and the absence of frequency dependence between X- and Q-band, support assignment of this additional process as a local mode. For these radicals the contributions from the local mode and the Raman process are correlated and follow trends in spin-orbit coupling. The temperature dependence of spin echo dephasing in sucrose octaacetate is dominated by rotation of methyl groups and by a motional process analogous to the Raman process.
Impact and interest:
Citation countsare sourced monthly fromand citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from theindexing service can be viewed at the linked Google Scholar™ search.
Full-text downloadsdisplays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
|Item Type:||Journal Article|
|Keywords:||Nitroxyl radicals, Spin, lattice relaxation, Raman process, Local mode, Volume scaling of thermodynamic parameters|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > PHYSICAL CHEMISTRY (INCL. STRUCTURAL) (030600) > Chemical Thermodynamics and Energetics (030602)|
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Science and Technology|
|Copyright Owner:||Copyright 2007 Taylor & Francis|
|Copyright Statement:||This is an electronic version of an article published in [Molecular Physics 105(15/16):pp. 2137-2151]. [Molecular Physics] is available online at informaworldTM with http://dx.doi.org/10.1080/00268970701724966|
|Deposited On:||10 Oct 2008|
|Last Modified:||29 Feb 2012 23:37|
Repository Staff Only: item control page