ISSN:
1434-6036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract 2H NMR spectra of copper acetate monohydrate [Cu(CD3CO2)2]·H2O, hexamethylbenzene-d18 and acetone-d6 were analyzed to characterize methyl group rotations between their classical and quantum mechanical limits. The temperature dependent spectra show the three different possible developments of the lineshapes. Hexamethylbenzene is typical of compounds with small but resolvable tunnelling frequencies. Characteristic splittings in the spectra of copper acetate monohydrate reveal the temperature dependence of tunnelling frequencies that are slightly larger than the quadrupole coupling constant. While the tunnelling frequency of acetone is already too large to be specified from2H NMR lineshape analysis at temperatures low enough that quantum effects influence the spectra, the temperature dependent spectra deviate characteristically from those found for classical rotation. Additionally to these experimental results, we outline how from an NMR point of view mixed classical and quantum rotations can be described by a single complex frequency.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01316710
