Rotational tunneling of partially deuterated methyl groups: Optical studies of dimethyl‐s‐tetrazine in different crystalline matrices

Thermal-cycling-induced spectral diffusion and thermal barriers in anisole-doped cyclohexane, an unusual multiphase host-guest system

The host-guest system of anisole incorporated into a cyclohexane matrix was investigated in a series of hole-burning experiments. This system is unusual in that cyclohexane can freeze into coexisting solid phases. The hole-burning experiments support the existence of two crystalline phases and one disordered phase. A second surprising characteristic of this system is that the quasi-line absorption features of the spectra appear inverted at low temperature because of unexpected dominance of fluorescence and phosphorescence.

Quantitative atom-atom potentials from rotational tunneling: their extraction and their use

Rotational tunneling of small molecular groups has been the subject of considerable theoretical and experimental activity for several decades. Much of this activity has been driven by the promise of exploiting the extreme sensitivity of quantum tunneling to interatomic potentials, but until recently, there was no straightforward means by which quantitative information about these potentials could be extracted. This review explains how a quantitative method, suitable for general application, was developed. It then goes on to show how this has been used to understand tunneling systems for which no previous satisfactory explanation had been found. The application of the methodology, and its results, to other disciplines is discussed.

A Systematic Approach for Determining Internal Rotation Potentials of Single-Top Molecules from Observed Transition Spectra

We present a systematic technique for the calculation of quantum potentials which fit experimentally specified transition spectra. With the aid of examples involving the molecular torsion of single-top molecules, we show how via a very small number of iterations, the observed spectrum may be approached to within a minimal deviation. Copyright 1997 Academic Press. Copyright 1997Academic Press