Abstract

In order to elucidate the localized nature of electrons in sugar/phosphate backbone in DNA molecules, resonant Auger decay spectra excited by soft x-rays around the inner-shell ionization thresholds have been measured for single-strand DNA. The systems investigated are thin films of DNA as well as related phosphorus compounds such as nucleotide (adenosine triphosphate, ATP), sodium phosphate, and indium phosphide. For ATP and DNA, it was observed that the resonant excitations from P $1s$ to valence unoccupied ${\ensuremath{\pi}}^{*}$ orbitals are followed by spectator-type Auger decays where the excited electrons remain in valence orbitals during the core-hole decays. It was also found that the energy of the P $K{L}_{2,3}{L}_{2,3}$ $(2{p}^{\ensuremath{-}1}∙{\ensuremath{\pi}}^{*})$ spectator Auger peak shifts linearly with the photon energy due to the resonant Auger Raman scattering. Most of the decay channel at the core-to-valence resonant excitation is spectator-type Auger decay in DNA, which is quite different from the Auger decay processes in metallic and semiconducting materials. We conclude that the excited electrons in valence unoccupied states around the phosphates in DNA molecules are strongly localized, resulting in the insulating properties in a one-dimensional direction along sugar/phosphate backbone.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.