Role of coherence in interaction of opticalradiation with macromolecules

Based on analysis of the properties of macromolecules in a coherent optical radiation field and taking into account experimentally established data on the specificity of the interaction between laser radiation and biomolecules (the dependence of the efficacy of the interaction on the coherence length, the presence of an effect in a region of the spectrum far away from the absorption band), we propose a mechanism for wave interaction of coherent optical radiation with macromolecules, and we construct a very simple mathematical model for such interaction. Using the mathematical model, we calculate the dependence of the vibrational energy of the macromolecule in a coherent radiation field on the coherence time and the intramolecular relaxation rate. We show that the increase in the vibrational energy of the macromolecules strongly depends on the radiation coherence length. When exposed to incoherent radiation, the vibrational energy of the biomolecules remains practically constant, while when exposed to laser radiation (coherence length ≈3 cm), the vibrational energy of the atoms increases by 2–4 orders of magnitude, leading to a change in the conformation of the biomolecules and the activity of enzymes. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 225–231, March–April, 2006.