A computational chemistry approach to environmental and public health

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State-of-the art computational chemistry will be used to explore the interaction of fields with biomolecules with direct implications to public and environmental health.   Ionizing radiation and electromagnetic fields EMFs are ubiquitous and are known to have several biochemical effects. The damage of biological molecules by ionizing radiation has seldom been investigated from the standpoint of the total electron density and its topology. We intend to study the effects of ionization on the electron density and reactivity indices of the DNA bases, the phosphate-sugar backbone of DNA, and the amino acids. Furthermore, the interaction of radiation with water itself results in the ejection of electrons which are immediately solvated by other water molecules. The structure and nature of the solvated electron, a subject of intense debate, will be studied using the quantum theory of atoms in molecules to examine the region(s) of space where it is (de)localized in model water clusters. At the other end of the electromagnetic spectrum lies the low frequency EMFs and which surround us in our modern civilization and represent a potential environmental and public health hazard. Unlike ionizing radiation, there is no universally-accepted molecular mechanism(s) for the observed biochemical effects of EMFs. We will model biochemical reactions in the presence and absence of fields to assess their perturbation of the potential energy surfaces, energy barriers, and reaction rates. The anticipated result will, in one stroke, provide a molecular picture and at the same time a quantitative measure of the perturbation (hazard) of biochemical reactions as a function of the field strength. Since most biochemical reactions occur in water, we are also highly motivated to develop a new computational strategy to circumvent the computational bottleneck that the inclusion of solvation represents. This will be achieved by "reconstructing" the solvation enthalpies of very large molecules from solvation enthalpies of small fragments. The interaction of the solvent with a molecule is yet another example of the interaction of a molecule with an external electrostatic field.