From the Theory of Chemical Lasers to the Spectra of High-Energy Density Materials Higher Order Conical Interactions Play a Key Role

摘要

Our AFOSR funded work has included both the development of new computational tools to determine photoelectron spectra within the time independent multimode vibronic coupling model, and the use of those tools, and techniques developed as part of other funded research, to determine photoelectron spectra for the selected azolides, anion precursors of the radical species, (CH)mN5-m, forw = 0-4. These anions have been suggested as components of ionic liquids and have been studied experimentally and computationally in Lineberger's group. Key to our ability to determine photoelectron spectra is an open-ended, fine-grained parallel algorithm for solving the nuclear Schrodinger equation using large vibronic bases. This algorithm was used to determine the negative ion photodetachment spectrum of the anion of pyrazolyl, (CH)mN5-m, for m = 3, whose determination, as recently as 2006, was declared computationally unfeasible. Work is currently finishing up on pyrrolyl, m = 4, is significantly in progress on triazolyl m = 2 and has begun on pentazolyl, m = 0. We have also studied a novel conical intersection topography in excited states of N3 + a potential photoionization probe of cyclic Nj, in which 3 symmetry equivalent seams of conical intersection are found in close proximity to a symmetry required seam. Finally, we have and will continue to do work on the role of conical intersections in the photodissociation of nitramines, which has been suggested as being relevant to the ignition process in HMX, RDX and related species.