Spectroscopic Search for Resonant Excitation of DNA by Microwaves.
Final rept. 11 Jul 84-ll Jul 86,
ARIZONA STATE UNIV TEMPE DEPT OF PHYSICS
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Inelastic laser light scattering is used to probe the vibrational modes of DNA that lie in the microwave frequency region. We have studied acoustic collective or sound wave vibrations in the region 7 - 20 GHz. in DNA films as they are hydrated. Taken together with an extensive study of the other physical properties of these films, these data show that strong interactions between phosphates dominate the dynamics in hydrated fibers. The relaxation of the hydration shell using Brillouin scattering is also studied. At GHz. frequencies, water couples strongly to acoustic vibrations. The viscoelastic transition frequency of the water at primary sites is about 4 GHz. while the secondary hydration shell undergoes this transition at about 80 GHz. Between these frequencies, there are coupled excitation of the DNA and its hydration shell which may account for the observed resonant microwave absorption. Direct spectroscopic evidence of these excitations was searched for without success. It is possible that an applied coherent microwave field must be applied to drive them.
- Organic Chemistry
- Atomic and Molecular Physics and Spectroscopy