Ultrafast Relaxation Dynamics of Uracil Probed via Strong Field Dissociative Ionization

We study the ultrafast relaxation dynamics of uracil excited to the first bright pi pi* state (S-2) by an ultrafast laser pulse in the deep ultraviolet (central wavelength lambda(0) = 260 nm). With a unique combination of strong field dissociative ionization measurements, state of the art strong field ionization calculations, and high level ab initio calculations of excited neutral and ionic states at critical points along the neutral potentials, we are able to gain a detailed picture of the relaxation dynamics of the molecule, which resolves earlier disagreements regarding measurements and calculations of the relaxation.