RESONANT DISSOCIATION OF DNA BASES BY SUBIONIZATION ELECTRONS

We have measured the electron energy dependence for production of a gr eat variety of anion fragments, induced by resonant attachment of subi onization electrons to thymine (T) and cytosine (C) within femto-secon d time scales. At the lowest electron energies we also observe stable molecular anions of these bases, viz., T- and C-. Our measurements sug gest that this resonant mechanism may relate to critical damage of irr adiated cellular DNA by subionization electrons prior to thermalizatio n. (C) 1998 American Institute of Physics. [S0021-9606(98)02504-5].