Potential energy surfaces for anion states of 5-chlorouracil

We present two-dimensional potential energy surfaces for the negative ions states π₁^*, π₂^* and σ_CCI^* of the potential radiosensetizer 5-chlorouracil. These were built along the C–Cl stretching mode (reactive coordinate) and an out-of-plane angular displacement of Cl atom (tuning coordinate), as obtained from scattering calculations performed with the Schwinger multichannel method. Analysis of the potential energy surfaces and quantum nuclear dynamics support that chloride elimination arises from an indirect mechanism around 1.5 eV, where the incoming electron is captured into a π^* orbital and is then transfered to the dissociative σ_CCI^* orbital. (paper)