Properties of DNA in the Far Infrared.
Abstract
We have carried out transmission measurements as a function of power for DNA films irradiated near the absorption maximum at 43/cm using the Santa Barbara Free Electron Laser. Initial results show no non-linear effects, such as bleaching, up to power densities of a few kW/sq cm. An experiment to search for unstacking of DNA bases when the molecule is exposed to intense radiation near the 'melting mode' frequency (approx. 80/cm) is nearing completion: exposure to available FEL power does not cause significant heating of the solution. Phonon damping mechanisms are being investigated in the range 0.1 to 200/cm by both Raman and Brillioun spectroscopy measurements made as a function of temperature and mode frequency. Coupling the relaxational motion of the hydration shell appears to be the main damping mechanism. At low (GHz.) frequencies, Debye-like reorientation of the bound water dominates the loss process, while at much higher frequencies, the hydrogen-bond breaking relaxations may contribute.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 12, 1987
- Accession Number
- ADA187143
Entities
People
- S. M. Lindsay
Organizations
- Arizona State University