{"title":"Pulsed electric dichroism studies of the amylose tri-iodide complex","authors":"A.R. Foweraker, B.R. Jennings","doi":"10.1016/0001-8716(74)80005-2","DOIUrl":"10.1016/0001-8716(74)80005-2","url":null,"abstract":"<div><p>The anisotropic optical absorption of macromolecules can be studied, when the molecules are in dilute solution, by subjecting the system to pulsed electric fields. Measurements were made on solutions of six amylose samples of varying molecular weights (<em>M</em>) in the range 1.4 × 10<sup>5</sup> to 1 × 10<sup>6</sup>, after the biopolymer had been complexed with iodine. The rates of molecular orientation enabled values of τ, the rotary relaxation time, to be obtained. When analysed, these indicated molecular flexibility. The “weakly-bending rod” model appeared to satisfy the experimental data, although a single value of the persistence length (<em>q</em>) did not describe the behaviour. As found in previous studies on other helical polymers, <em>q</em> varied continuously with <em>M</em>. The electrical properties and the degree of orientation in the field indicated that only induced and not permanent dipole moments were present. These induced dipole moments were analysed in terms of an anisotropy of the molecular polarisability. This was consistent with the model of a flexible helix. A value of 28 × 10<sup>−24</sup> F m was evaluated for the excess polarisability difference per helical pitch. Values of the molecular extinction coefficients for light of wavelength 625 nm when polarised parallel to and perpendicular to the individual helix axes, indicated that the relevant electronic transition is not confined to the long helical axis as had been previously assumed.</p></div>","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 3","pages":"Pages 241-254"},"PeriodicalIF":0.0,"publicationDate":"1974-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80005-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87455914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"13C Spectral assignment and spin-lattice relaxation in medium-sized molecules","authors":"Felix W. Wehrli","doi":"10.1016/0001-8716(74)80007-6","DOIUrl":"10.1016/0001-8716(74)80007-6","url":null,"abstract":"<div><p>The individual <sup>13</sup>C spin-lattice relaxation times in three molecules of different molecular size - codeine, brucine and reserpine - have been determined. In all three molecules, <em>T</em><sub>1</sub> for methine carbons, being part of the isotropically reorientating skeleton, ranges from 0.15 to 0.23 sec corresponding to reorientational correlation times of 3 × 10<sup>−10</sup> and 2 × 10<sup>−10</sup> sec. All carbons, including the quaternaries, ar shown to be relaxed through dipole-dipole interaction. The relaxation rate of non-proton-bearing carbons is found to be governed by geminal and vicinal protons thus allowing reliable assignments to be made that are unavailable from other techniques. The peak heights in completely relaxed <sup>13</sup>C Fourier transform spectra of medium-sized molecules are shown to reflect spin-spin relaxation, thus permitting a qualitative estimate of this parameter. As an example, the spectrum of 3-cholestanone is discussed.</p></div>","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 2","pages":"Pages 139-151"},"PeriodicalIF":0.0,"publicationDate":"1974-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80007-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90756836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Theoretical analysis of the lumped capacitance method in dielectric time domain spectroscopy","authors":"M.J.C. van Gemert","doi":"10.1016/0001-8716(74)80006-4","DOIUrl":"10.1016/0001-8716(74)80006-4","url":null,"abstract":"<div><p>A theoretical analysis is presented of the lumped capacitance method and its small capacitance approximation using a Debye dielectric permittivity relation and low frequency conductivity. The influence of fringing fields are discussed. The results of the small capacitance method are compared with those for the thin cell method.</p></div>","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 2","pages":"Pages 123-137"},"PeriodicalIF":0.0,"publicationDate":"1974-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80006-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90607354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Determination of thermal relaxation times by the impact tube method study of vibration-translation and vibration-vibration exchanges in CO2, N2O and CH4 pure or mixed with other gases","authors":"M. Huetz-Aubert, R. Lenormand, H. Manceau","doi":"10.1016/0001-8716(74)80008-8","DOIUrl":"10.1016/0001-8716(74)80008-8","url":null,"abstract":"","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 2","pages":"Pages 153-170"},"PeriodicalIF":0.0,"publicationDate":"1974-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80008-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90905979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chemical exchange and NMR-T2 relaxation","authors":"J. Jen","doi":"10.1016/0001-8716(74)80009-X","DOIUrl":"10.1016/0001-8716(74)80009-X","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":0.0,"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":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73833834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Formation of beryllium sulphate complexes in aqueous solutions","authors":"W. Knoche, C. A. Firth, D. Hess","doi":"10.1016/0001-8716(74)80012-X","DOIUrl":"https://doi.org/10.1016/0001-8716(74)80012-X","url":null,"abstract":"","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"47 1","pages":"1-17"},"PeriodicalIF":0.0,"publicationDate":"1974-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73069858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluation of relaxation parameters according to budó equations","authors":"J. Crossley, S.P. Tay, S. Walker","doi":"10.1016/0001-8716(74)80018-0","DOIUrl":"https://doi.org/10.1016/0001-8716(74)80018-0","url":null,"abstract":"","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 1","pages":"Pages 79-83"},"PeriodicalIF":0.0,"publicationDate":"1974-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80018-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89988768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the notion of dielectric friction in the theory of dielectric relaxation","authors":"T. Tjia, P. Bordewijk, C. Böttcher","doi":"10.1016/0001-8716(74)80013-1","DOIUrl":"https://doi.org/10.1016/0001-8716(74)80013-1","url":null,"abstract":"","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"258 1","pages":"19-28"},"PeriodicalIF":0.0,"publicationDate":"1974-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74513553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Alternative interpretations of dielectric measurements with particular reference to polar liquids","authors":"R.J. Sheppard, E.H. Grant","doi":"10.1016/0001-8716(74)80016-7","DOIUrl":"https://doi.org/10.1016/0001-8716(74)80016-7","url":null,"abstract":"","PeriodicalId":100050,"journal":{"name":"Advances in Molecular Relaxation Processes","volume":"6 1","pages":"Pages 61-67"},"PeriodicalIF":0.0,"publicationDate":"1974-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-8716(74)80016-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91629367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}