Chemischer InformationsdienstVolume 7, Issue 11 Physical Organic Chemistry ChemInform Abstract: NUCLEAR MAGNETIC RESONANCE STUDY OF MOLECULAR ROTATION AND SELF-DIFFUSION IN SOLID BENZENE- T1ϱ-SPECTROSCOPY F. NOACK, F. NOACKSearch for more papers by this authorM. WEITHASE, M. WEITHASESearch for more papers by this authorJ. VON SCHUETZ, J. VON SCHUETZSearch for more papers by this author F. NOACK, F. NOACKSearch for more papers by this authorM. WEITHASE, M. WEITHASESearch for more papers by this authorJ. VON SCHUETZ, J. VON SCHUETZSearch for more papers by this author First published: March 16, 1976 https://doi.org/10.1002/chin.197611041AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue11March 16, 1976 RelatedInformation

Abstract We have extended previous NMR investigations of the molecular motion in solid benzene to lower proton spin Larmor frequencies using the rotating frame (T1ϱ) technique. The new data show two relaxation mechanisms, namely the well-known rotation of the benzene rings around their sixfold axis and, additionally, the self-diffusion by vacancies. The rotation and diffusion was analyzed by computer optimization of the relaxation models of Haeberlen and Torrey, respectively. The parameters of rotation are essentially consistent with results derived recently from high-frequency T1 measurements. The diffusion parameters are in agreement with preliminary low-frequency T1 measurements, but reveal a dramatic discrepancy by nearly 4 orders of magnitude with respect to tracer experiments of Fox and Sherwood. This behaviour is discussed in terms of correlation effects similar to those observed in plastic and liquid crystals.

We report on measurements of the63Cu nuclear spin relaxation time in the rotating frame,T1ρ, in solid copper as a function of temperature and Larmor frequency, from which the temperature dependence of the self-diffusion coefficient was evaluated using Torrey's theory. Within the relatively small temperature range (572 °C ≦ ϑ ≦ 838 °C) in which diffusion relaxation dominates, the temperature dependence of the diffusion coefficient is compatible with a simple Arrhenius law. However, in an evaluation including recent tracer results in an essentially larger temperature range (353 °C≦ϑ≦1079 °C) clear deviations from this standard interpretation were found, as implied by Seeger's divacancy formalism. From those deviations we have calculated a more reliable set of diffusion parameters than comparable data in the literature.

physica status solidi (b)Volume 57, Issue 2 p. K111-K115 Short Note Kernmagnetische Spinrelaxation durch Selbstdiffusion in festem Lithium 7Li:T1, -Frequenzabhängigkeit M. Weithase, M. Weithase Physikalisches Institut (4) der Universität StuttgartSearch for more papers by this authorF. Noack, F. Noack Physikalisches Institut (4) der Universität StuttgartSearch for more papers by this author M. Weithase, M. Weithase Physikalisches Institut (4) der Universität StuttgartSearch for more papers by this authorF. Noack, F. Noack Physikalisches Institut (4) der Universität StuttgartSearch for more papers by this author First published: 1 June 1973 https://doi.org/10.1002/pssb.2220570246Citations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Literatur 1 C. Slighter und D. Ailion, Proc. XIIIth Coll. Ampère, Leuven 1964 (S. 70). 2 C. Slighter und D. Ailion, Phys. Rev. 135, A1099 (1964). 3 D. Ailion and C. Slighter, Phys. Rev. 137, A235 (1965). 4 D. Anderson und A. Redfield, Phys. Rev. 116, 583 (1959). 5 D. Holcomb und R. Norberg, Phys. Rev. 98, 1074 (1955). 6 R. Messer, F. Noack und A. Seeger, Phys. stat. sol. (b), in Vorbereitg.; Verhandl. DPG (VI) 7, 678 (1972). 7 H. Torrey, Phys. Rev. 92, 962 (1953); Phys. Rev., 96, 690 (1954). 8 M. Weithase, F. Noack und J. von Schütz, Z. Phys. 246, 91 (1971); Z. Naturf., in Vorbereitung. 9 D. Douglass und G. Jones, J. chem. Phys. 45, 956 (1966). 10 G. Jones, Phys. Rev. 148, 332 (1966). 11 D. Ailion, Adv. Magnetic Resonance 5, 177 (1971). 12 B. Blicharski, Acta Phys. Polon. A41, 223 (1972). 13 A. Ott, J. Mundy, L. Löwenberg und A. Lodding, Z. Naturf. 23a, 771 (1968). 14 A. Seeger und H. Mehrer, in: Vacancies and Interstitials in Metals, North-Holland Publ. Co., Amsterdam 1970 (S. 1). Citing Literature Volume57, Issue21 June 1973Pages K111-K115 ReferencesRelatedInformation

Measurements of the rotating frame proton spin relaxation timeT1p in hexagonal ice single crystals as a function of temperature ϑ for various rotating magnetic field strengths reveal the expectedT1p minimum at the lowest practicable field values. This allows a very precise determination of the proton correlation (≜ molecular jump) time τc and the related activation energy ΔE by means of the theoretical reasoning of relaxation spectroscopy. We find the Arrhenius-law temperature dependenceτc=1.99×10−17exp(0.603/8.61×10−5 ϑ)sec, which is in good agreement with our earlier indirect derivation.

Proton spin-lattice relaxation timesT1 in hexagonal ice have been measured from −10 to −80°C for different external Zeeman fieldsHR from 0.125 to 6.57 kOe. The results can be described byT1∼H R 2 exp(ΔEc/kT) (ΔEc=activation energy). In pure ice (HR ∥c-axis)ΔEc is 0.62 eV, whereas relaxation due to impurities givesΔE′c≈0.25 eV. The analysis of these results including additional data of the dielectric relaxation and the self-diffusion coefficient yields thatT1 in pure ice is determined mainly by the motion of Schottky defects. Bjerrum faults give an additional but small contribution. SettingT1=C·τc (τc=molecular correlation time which is proportional to exp(ΔEc/kT), C=constant depending onHR and molecular distances) we calculatedC with the model mentioned above and found e.g. 0.88 · 106 atHR=6.57 kOe.E′c≈0.25 eV is assumed to be the energy of migration of Bjerrum and ionic faults.