title: Determination of T1-spin-lattice relaxation time in a two-level system by continuous wave multiquantum electron paramagnetic resonance spectroscopy in a presence of tetrachromatic microwave irradiation.
abstract: Applicability of continuous wave multiquantum EPR methods to study relaxation times at X-band is examined. Multiquantum transitions excited in a two-level system by tetrachromatic irradiation are used for these studies. The Bloch equation model is applied to simulate lineshapes of the three quantum transitions as a function of frequency difference between exciting fields. The dependence of multiquantum transition signals on relaxation times and microwave amplitude is shown. On this basis a method of deducing relaxation times from these signals is formulated. The case of a homogeneously and inhomogeneously broadened resonance line is considered. Two experimental methods are used to verify the proposed hypothesis: the X-band continuous wave multiquantum EPR with four frequencies microwave field and saturation recovery EPR. The values of T(1) obtained from CW MQ EPR and SR EPR are compared.
authors.affiliation: Department of Biophysics, Faculty of Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland. mdutka@mol.uj.edu.pl
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Dutka
authors.forename: Ryszard J
authors.initials: RJ
authors.lastname: Gurbiel
authors.forename: Jerzy
authors.initials: J
authors.lastname: Kozioł
authors.forename: Wojciech
authors.initials: W
authors.lastname: Froncisz
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D008872:Microwaves; D009589:Nitrogen Oxides / Q000737:chemistry*; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels
chemical_list: D009589:Nitrogen Oxides; D013113:Spin Labels