Dynamics of initial ionization events in biological molecules: Formation and fate of free radicals. Final technical report, May 1, 1994--December 31, 1995

Study of early time events following the absorption of electromagnetic radiation in biological systems has potentially significant impact on several areas of importance. In this context, the studies being conducted under this program provided insight into the conformational changes as well as the reactions leading to a variety of transformations that culminate from hydrogen atom and proton transfer events. These studies enabled an investigation of molecular details of structure-function relationships. In a second aspect of the program, investigations were conducted to provide basic underpinning research that contributed to a quantification of the behavior of radionuclides and pollutants associated with advanced energy activities after these materials emanate from their source and become transferred through the environment to the biota and human receptor. The approach to elucidating factors governing the difference between reactions in the gas and condensed phase was to study the initiating steps at progressively higher degrees of cluster aggregation. The author employed ultrafast laser techniques, in combination with selected molecules, carefully prepared in tailored compositions, to investigation the primary mechanisms involved in various molecular functional groups following the absorption of electromagnetic radiation. He also studied various molecules representing chromophores in such biologically important molecules as tyrosine and amines