Forcing Electrons To Flow Through Water

Today’s news leads on very well from yesterday’s as it is likewise looking at the physics of secondary low energy electrons, very specifically the effect of these electrons on water, the main components of most cells. Despite the electrons being relatively low energy, with most not surpassing about 10 eV, some acute damage can still be done and it was found about a decade ago that the damage DNA receives does not necessarily scale with energy of the damaging electrons. In order to understand the exact interaction of electrons with the water in cells many experiments have been carried out to attempt to understand the process of the electrons transferring energy. This study aims to improve on this kind of work by offering a more advanced and specialised model for the water that makes it act in a much more similar way the liquid found in cells. Details about the electron configuration along with bonding and antibonding electrons were imputed. The phonons within the water were only given one standing wave state which represents the limited environments the water would be in within a cell.

Taking ten water molecules in a sample, these were then “injected” through minuscule metal connections with the electrons in pulses. Through a series of simulations  the electron absorption into the water could be measured. This was modelled for both when the electrons underwent perfect elastic collisions but also when significant energy was lost in each interaction. It was found that there are likely two effects that are leading to the loss and dispersion of energy from the electrons. The first is simply the phonon vibrations effecting the environment, likely through hydrogen bonds as suggested in the paper. If the energy being supplied is great enough the vibrations progress to a point that modelling the atoms as harmonic oscillators becomes insufficient. Due to the rapid and complex vibrations, some bonds are likely to break taking some energy when they do so. Ultimately the classical description of the system is easily deviated from provided the incoming electrons have sufficient energy. Understanding the dynamics of electrons and water in such detail will always be a computationally taxing task but this leads cleanly on to topics about cell damage and being able to accurately model that.

Paper links: Inelastic electron injection in a water chain

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