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A 2H NMR spin-lattice relaxation study of -NH3poststaggered+ group dynamics in polycrystalline l-alanine

✍ Scribed by M.A.K. Williams; R.D. Keenan; T.K. Halstead

Publisher
Elsevier Science
Year
1996
Tongue
English
Weight
575 KB
Volume
6
Category
Article
ISSN
0926-2040

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✦ Synopsis

The 2H spin-lattice relaxation times T1Z and T1Q of the -ND+3 group in polycrystalline L-alanine were measured over the temperature ranges 250-425 K and 300-425, respectively. The relaxation data were fitted to analytical expressions for three-fold reorientation, giving a correlation time tau(c) = 1.5 x 10(-14) s exp(40.2 kJ mol-1/RT), which is in good agreement with the results of a limited lineshape study. T 1Z values derived from numerical simulations, taking into consideration geometrical distortion of the -ND+3 group and experimental imperfections, are compared with values given by an analytical expression for three-fold jumps and with the experimental results. The extraction of average site quadrupolar coupling constants is discussed.

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