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Title: Study of correlations in molecular motion by multiple quantum NMR

Nuclear magnetic resonance is a very useful tool for characterizing molecular configurations through the measurement of transition frequencies and dipolar couplings. The measurement of spectral lineshapes, spin-lattice relaxation times, and transverse relaxation times also provide us with valuable information about correlations in molecular motion. The new technique of multiple quantum nuclear magnetic resonance has numerous advantages over the conventional single quantum NMR techniques in obtaining information about static and dynamic interactions of coupled spin systems. In the first two chapters, the theoretical background of spin Hamiltonians and the density matrix formalism of multiple quantum NMR is discussed. The creation and detection of multiple quantum coherence by multiple pulse sequence are discussed. Prototype multiple quantum spectra of oriented benzene are presented. Redfield relaxation theory and the application of multiple quantum NMR to the study of correlations in fluctuations are presented. A specific example of an oriented methyl group relaxed by paramagnetic impurities is studied in detail. The study of possible correlated motion between two coupled methyl groups by multiple quantum NMR is presented. For a six spin system it is shown that the four-quantum spectrum is sensitive to two-body correlations, and serves a ready test of correlated motion. The study ofmore » the spin-lattice dynamics of orienting or tunneling methyl groups (CH/sub 3/ and CD/sub 3/) at low temperatures is presented. The anisotropic spin-lattice relaxation of deuterated hexamethylbenzene, caused by the sixfold reorientation of the molecules, is investigated, and the NMR spectrometers and other experimental details are discussed.« less
Authors:
Publication Date:
OSTI Identifier:
5582121
Report Number(s):
LBL-13605
ON: DE82005650; TRN: 82-007136
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis
Research Org:
Lawrence Berkeley Lab., CA (USA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 74 ATOMIC AND MOLECULAR PHYSICS; AROMATICS; SPIN-LATTICE RELAXATION; DEUTERIUM COMPOUNDS; HYDROCARBONS; MOLECULAR STRUCTURE; CORRELATIONS; MOLECULES; NUCLEAR MAGNETIC RESONANCE; COUPLING; DIPOLES; FLUCTUATIONS; HAMILTONIANS; MOTION; NMR SPECTROMETERS; SPIN; ZEEMAN EFFECT; ANGULAR MOMENTUM; HYDROGEN COMPOUNDS; MAGNETIC RESONANCE; MATHEMATICAL OPERATORS; MEASURING INSTRUMENTS; MULTIPOLES; ORGANIC COMPOUNDS; PARTICLE PROPERTIES; QUANTUM OPERATORS; RELAXATION; RESONANCE; SPECTROMETERS; VARIATIONS 400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987); 640302 -- Atomic, Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory