The Dynamics of Methyl-like Quantum Rotors in NMR Spectra

THE DYNAMICS OF METHYL-LIKE QUANTUM ROTORS IN NMR SPECTRA 

Unlike for the metal hydrides, for methyl-like quantum rotors the pairwise exchanges are unfeasible. On the other hand, cyclic permutations of the three like particles constituting the rotor are relevant. Thus, the feasible group of interest is C3. Basic concepts used in the NMR theories of the methyl-type rotors are described in the caption to Fig. 8. 

Until recently, the quantum nature of the problem was being taken into account only in NMR studies at cryogenic temperatures. At such temperatures, the coherent behaviour is prevalent. The formalism affording theoretical description of the observed spectra involves augmentation of the standard solid-state NMR Hamiltonian with the conesponding tunnelling term [c.f. Eq. (4)], 

The above interpretation has recently been challenged the recent results for a CD3 rotor at cryogenic temperatures (to be described in the sequel) show for the first time that consequences of the symmetrization postulate involve the stochastic dynamics as well.  

Developments in theory the damped quantum rotor model 

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The Dynamics of Methyl-like Quantum Rotors in NMR Spectra... 

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