Tunneling rotation

Among numerous examples of the role of the chemical structure in tunneling rotation we select just one, connected with the effect of intramolecular hydrogen bond. In acetyl acetone in stable enol form... 

T. Baba, T. Tanaka, I. Morino, K. M. T. Yamada, and K. Tanaka, Detection of the tunneling rotation transitions of malonaldehyde in the submillimeter wave region. /. Chem. Phys. 110, 4131 4133 (1999). 

The dynamics of tunneling rotation of hindered rotors interacting with intra- and intermolecular vibrations has received much less attention than structural studies. Such interactions shift and broaden tunneling spectral lines and, when temperature is raised, lead to transitions from coherent tunneling to thermally activated hopping. 

Tunneling rotation of three-dimensional coupled rotors in solid methane is dealt with in many experimental and theoretical studies. The phase transition at 20.4 K turns this species from orientationally disordered phase I to partially oriented phase II. According to neutron... 

Tunneling rotation in the chain gives rise to tunneling states, which can be labeled by the wave vector ranging within the first Brillouin zone ... 

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