arXiv subjects
Publications and source records attributed to Voislav Golo.
We find a parametric resonance in the GHz range of the DNA dynamics, generated by pumping hypersound . There are localized phonon modes caused by the random structure of elastic modulii due to the sequence of base pairs.
We study a model for pair interaction $U$ of DNA molecules generated by the discrete dipole moments of base-pairs and the charges of phosphate groups, and find noncommutative group of eighth order ${\cal S}$ of symmetries that leave $U$ invariant. We classify the minima using group ${\cal S}$ and employ numerical methods for finding them. The minima may correspond to several cholesteric phases, as well as phases formed by cross-like conformations of molecules at an angle close to $\rm{90}^{o}$, "snowflake phase". The results depend on the effective charge $Q$ of the phosphate group which can be modified by the polycations or the ions of metals. The snowflake phase could exist for $Q$ above the threshold $Q_C$. Below $Q_C$ there could be several cholesteric phases. Close to $Q_C$ the snowflake phase could change into the cholesteric one at constant distance between adjacent molecules.
We consider the regime in which the bands of the torsional acoustic (TA) and the hydrogen-bond-stretch (HBS) modes of the DNA interpenetrate each other. Within the framework of a model that accommodates the structure of the double helix, we find the three-wave interaction between the TA- and the HBS-modes, and show that microwave radiation could bring about torsional vibrations that could serve as a pump mode for maintaining the HBS-one. Rayleigh's threshold condition for the parametric resonance provides an estimate for the power density of the mw-field necessary for generating the HBS-mode.