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Title: | Temperature Dependent Anisotropic Line Splitting And Linewidth In Motionally Averaged Epr Spectra Of Ch3 Radicals In Solid Ar |
Author(s): | Dmitriev, Yurij |
Contributor(s): | Benetis, Nikolas Ploutarch |
Subject(s): | Matrix isolation (and droplets) |
Abstract: | Rotational dynamics is one of the most fascinating features of molecular solids. This report presents EPR studies of methyl radical rotation in solid Ar, a matrix possessing no nuclear magnetic moments that facilitates recording magnetic resonance spectra of high resolution. As a result, we were able to make a thorough investigation of the lineshape temperature behavior of the A- and E-symmetry multiplets related to different rotational states of the radical. Methyl radicals in solid Ar matrix were recorderd at the liquid helium temperature 4.2 K and in the range from 9 through 31 K. Both EPR multiplets exhibited anisotropic features which were explained by a model accounting for fast rotation about the radical C$_{3}$ axis and relatively slow reorientation about the in-plane C$_{2}$ axes. We present the first observation of anisotropic splitting in the powder EPR of methyl radical E-states suggesting that the A- and E- rotational states which differ in their spatial characteristics should exhibit a varying degree of coupling to the surrounding cage in the matrix. The simulation model of the E-state doublet was tentatively based on the transition of radical dynamics from rotational jumps at low temperatures to rotational diffusion at high temperatures with a conditional border 19 K. For the molecule in A-state , temperature assisted tunneling was supposed to occur at temperatures below 16 K while temperature activated rotational diffusion was taking place at higher temperatures.\footnote{Y. D. acknowledges a partial financial support from Russian Foundation for Basic Research under grant 13-02-00373-a.} |
Issue Date: | 2014-06-19 |
Publisher: | International Symposium on Molecular Spectroscopy |
Citation Info: | Dmitriev, Y.; Benetis, N.P. TEMPERATURE DEPENDENT ANISOTROPIC LINE SPLITTING AND LINEWIDTH IN MOTIONALLY AVERAGED EPR SPECTRA OF CH3 RADICALS IN SOLID Ar. Proceedings of the International Symposium on Molecular Spectroscopy, Urbana, IL, June 16-21, 2014. DOI: 10.15278/isms.2014.RI09 |
Genre: | CONFERENCE PAPER/PRESENTATION |
Type: | Text |
Language: | English |
URI: | http://hdl.handle.net/2142/50934 |
DOI: | https://doi.org/10.15278/isms.2014.RI09 |
Rights Information: | Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/ |
Date Available in IDEALS: | 2014-09-17 2015-04-14 |