{"title":"Chemical exchange and NMR-T2 relaxation","authors":"J. Jen","doi":"10.1016/0001-8716(74)80009-X","DOIUrl":null,"url":null,"abstract":"<div><p>The decay of the amplitude for a Carr-Purcell train of echoes in a system with two exchanging sites is investigated. Closed expressions are derived which are valid for all values of the chemical shift, the two transverse relaxation times, and the two average lifetimes. Previously published solutions to this problem considering pulsed and continuous-wave <span>NMR</span> methods emerge as special cases of the treatment presented in this paper. The analysis shows that high-pulse rates eliminate the effect of the chemical shift on the <span>NMR</span> relaxation but that the effect of the chemical exchange disappears only in special cases. A computer program (FORTRAN V)<span><sup>1</sup></span> is available for the calculation of spin-echo decay times with a given set of parameters and for the reverse task of evaluating parameters from the experimental data.</p></div>","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 2","pages":"Pages 171-183"},"PeriodicalIF":0.0000,"publicationDate":"1974-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80009-X","citationCount":"24","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in Molecular Relaxation Processes","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/000187167480009X","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 24
Abstract
The decay of the amplitude for a Carr-Purcell train of echoes in a system with two exchanging sites is investigated. Closed expressions are derived which are valid for all values of the chemical shift, the two transverse relaxation times, and the two average lifetimes. Previously published solutions to this problem considering pulsed and continuous-wave NMR methods emerge as special cases of the treatment presented in this paper. The analysis shows that high-pulse rates eliminate the effect of the chemical shift on the NMR relaxation but that the effect of the chemical exchange disappears only in special cases. A computer program (FORTRAN V)1 is available for the calculation of spin-echo decay times with a given set of parameters and for the reverse task of evaluating parameters from the experimental data.
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