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Methyl And Tert-Butyl Reorientation And Distributions Of Activation Energies In Molecular Solids: A Nuclear Spin-Relaxation Study In 2,4- And 2,5-Di-Tert-Butylhydroxybenzene, Peter A. Beckmann, A. M. Cheung, E. E. Fisch, F. A. Fusco, R. E. Herzog, M. Narisimhan
Methyl And Tert-Butyl Reorientation And Distributions Of Activation Energies In Molecular Solids: A Nuclear Spin-Relaxation Study In 2,4- And 2,5-Di-Tert-Butylhydroxybenzene, Peter A. Beckmann, A. M. Cheung, E. E. Fisch, F. A. Fusco, R. E. Herzog, M. Narisimhan
Physics Faculty Research and Scholarship
We have measured proton Zeeman relaxation rates R in the 2,4- and 2,5-isomers of di tert-butylhydroxybenzene (DTHB) in the solid state. R was measured as a function of temperature T at proton Larmor frequencies of (j)/21T = 8.50,22.5, and 53.0 MHz. The Tranges were from 78 K to just below the melting points of 2,4- and 2,5-DTHB, 385 and 323 K, respectively. The 2,5- DTHB R vs T and (j) can be interpreted qualitatively in terms of three Bloembergen-PurcellPound (BPP) spectral densities, one for each of the three types of rotors in the molecule. The quantitative agreement is poor but …
Deuteron Zeeman Relaxation Of Cd4 In The Isotropic Liquid, The Liquid Crystalline, And The Solid State Of Several Substances, Peter A. Beckmann, Myer Bloom, E. Elliott Burnell
Deuteron Zeeman Relaxation Of Cd4 In The Isotropic Liquid, The Liquid Crystalline, And The Solid State Of Several Substances, Peter A. Beckmann, Myer Bloom, E. Elliott Burnell
Physics Faculty Research and Scholarship
Measurement of deuteron Zeeman relaxation rates of CD4 dissolved in benzene, hexane, and the liquid crystals MBBA, EBBA, and Merck ZLI‐1132 and in pure CD4 gas as a function of temperature at 30.7 and 61.4 MHz shows that the CD4 is uniformly dispersed in the liquid solvents but resides in gas pockets when the solvents are in the solid state. Effects of centrifugal distortion were observed in the gas phase. The relaxation rate was found to be nearly independent of solvent, temperature, and pressure for the methane–liquid mixtures. This result is explained in terms of the extended …
Nuclear Magnetic Resonance Spectroscopy And Relaxation In Molecular Solids Containing Isopropyl Groups. Part 2—The Large Two-Phase Temperature Region In 1,4-Di-Isopropylbenzene, Peter A. Beckmann
Physics Faculty Research and Scholarship
We report a proton n.m.r. study of the large, long-lived two-phase temperature region in 1,4-di-isopropylbenzene (DIB). The proton spectra are characterized by a narrow line superimposed on a 42 kHz broad line. The narrow line shows the chemical shift structure of DIB. When the sample is in the solid state the narrow lines are sharp (<30 Hz) near the melting point of 256 K and they broaden to ca.1.5 kHz at ca. 170 K where they disappear. A variety of selective and non-selective Zeeman relaxation experiments as well as a Goldman–Shen exchange experiment were performed. It is concluded that the two sets of spins do not communicate on any timescale shorter …