A Discussion on Information Entropy of Molecular Tunneling

Molecular tunneling process has been considered by means of radiation theory. The formula for
information entropy calculation has been derived by means of interaction model of thermal equilibrium
radiation with a molecule at low temperatures. The physical meaning of information entropy for lowtemperature
plateau of unimolecular chemical reaction 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
conversion takes place at a temperature when the average energy of the elementary activation act is
equal to a part of zero energy of the transforming molecule. Two unimolecular reactions have been
investigated. These are Fe-CO bond recombination in β-hemoglobin and double proton transfer in
benzoic acid dimer for sequential deuteration of hydrogen bond and various hydrostatic pressures.
Using the information entropy formula it is possible to calculate its value in energy units of
measurements for low-temperature plateau. Probabilities of occurrence of the reactions under
considerations, their efficiency and mean-square fluctuations of the distribution function parameters
have also been determined. The proposed interaction model of thermal equilibrium radiation with a
molecule at low temperatures describes the process by using a distribution function. The function
represents an activation barrier as the molecule’s sub-conformation states set. All the states share a
common trait, that of providing the tunneling process by means of a part of zero-point vibrations
energy.