Time-dependent density-functional-theory investigation of the collisions of protons and α particles with uracil and adenine

Abstract

Time-dependent density-functional theory was employed to study the effects of proton and $\ensuremath{\alpha}$-particle radiation on uracil and adenine. This method has the advantage of treating nuclear motion and electronic motion simultaneously, allowing for the study of electronic excitation, charge transfer, ionization, and nuclear motion. Particle energies were surveyed in the range of 15--500 keV for protons and 100--2000 keV for $\ensuremath{\alpha}$ particles in conjunction with impact points both on and off carbon bonds in order to investigate the electron and nuclear dynamics of irradiated molecules and the form and quantity of transferred energy. The stopping power, energy transferred, and ionization were found, and the relationship between incident particle energy and electron density of the target molecule was characterized for proton and $\ensuremath{\alpha}$-particle radiation incident on adenine and uracil.