DNA Microwave Response.
Annual rept. May 86-May 87,
PURDUE UNIV LAFAYETTE IND DEPT OF PHYSICS
Pagination or Media Count:
The expected absorption of microwave radiation in the gigaHertz frequency range by fixed length DNA polymer molecules disolved in saline solution is calculated. While the effects of counterions and solvent dynamics have been accounted for in detail, the features of the absorption are completely dominated by the interaction between the charged polymer molecule and the so called first hydration layer, that is, the nearest layer of solvent water molecules not actually bonded to the polymer. The relevant parameters of this interaction are the strength of the water to polymer coupling and the average persistence time of individual water to polymer bonds. A high accuracy software package is developed for calculating a complete phonon dispersion spectrum for any DNA polymer configuration utilizing classical dynamics via a dynamical force constant matrix. These routines permit us to treat a variety of related physical systems with a minimum of attention to computing detail. Mean helix parameters are selected over their allowed experimental ranges and the particular values determined which yield a Helmholtz free energy minimum.
- Radiofrequency Wave Propagation