Activation process for unimolecular reaction has been considered by means of radiation theory. The formulae of information entropy of activation have been derived for the Boltzmann–Arrhenius model and the activation process model (APM). The physical meaning of this entropy has been determined. It is a measure of conversion of thermal radiation energy to mechanical energy that moves atoms in a molecule during elementary activation act. It is also a measure of uncertainty of this energy conversion. The uncertainty is due to unevenness of distribution function representing the activation process. It has been shown that Arrhenius dependence is caused by the entropy change. Efficiency comparison of the two models under consideration for low-temperature fluctuations of a myoglobin molecule structure shows that the APM should be favored over the Boltzmann–Arrhenius one.

Earlier obtained two-dimensional ~H-NMR spectroscopy data were used to analyze the spatial structure and conformational mobility of the double right TI 1rlr7~ helix of the complex formed by gramicidine A and Cs ÷ ions in an organic solvent (a chloroform-methanol mixture). Analysis of the experimental data permitted the determination of a set of conformations for each of the high-mobility residue side chains in the solution. The energy refinement of the most probable conformation of the double right 11 7.2 ~'TrLo helix was made and conformational rearrangements of the tryptophan residue side chain were studied in detail.

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