Three-wave interaction between interstrand modes of the DNA

We consider the regime in which the bands of the torsional acoustic (TA) and hydrogen-bond-stretch (HBS) modes of DNA interpenetrate each other. We propose a simple model accommodating the helix structure of DNA and, within its framework, find a three-wave interaction between the TA and HBS modes. The phenomenon could be useful for studying the action of microwave radiation on a DNA molecule. Thus, using Zhang’s mechanism of the interaction between the system of electric dipoles of a DNA molecule and microwave radiation, we show that the latter could bring about torsional vibrations that maintaining HBS vibrations. We show an estimate of the microwave power density necessary for generating the HBS mode, which significantly depends on the viscous properties of the ambient medium.