The mean ionization potential of DNA and Liquid water

The Partial Stopping Power Effective Charge (PSPEC) ζ(q), the mean excitation energy I(eV), have been determined in target DNA and H2O in the present work we use the Drude-dielectric formalism to calculate the effects of contribution of inner and outer-electron shell to energy-loss of protons in two targets of high biological interest, namely, H2O and DNA. For a better control and understanding of the effects of radiation damage in living tissues, it is necessary to advance an accurate description of the energy loss from the ion beam to the target. The results show that the charged particles (protons) with energy between 0.05 MeV to 2.5 MeV are very efficient in producing secondary electrons in dry DNA, which are able to produce strand breaks and could be very effective for the biological damage of malignant cells. An effort to study the interaction of energetic ion beams with liquid water H2O at intermediate energies has been carried out recently, since water represents over 80% of the content of the cells of soft tissues. Screening length effects has been taken in the consideration and good agreement is achieved with previous work using Isabel Abril [1] for numerical calculations in the program.