Search for the plasmon in condensed water

Creation of plasmons in water by energetic particles in biological tissue is important because this form of energy can migrate from the place of excitation and be transferred to nearby molecules like DNA. We have searched for evidence of plasmons in solid water, using electron-energy-loss and secondary electron spectroscopies excited by 70–1000-eV electrons. We find that the energy of the main excitation, often attributed to plasmons, depends on the energy of the exciting electron, unlike the expected plasmon behavior. The energy spectrum of secondary electrons shows the presence of autoionization, but no evidence of plasmon decay.