Jeffrey A. Cina of the University of Oregon is supported by the Chemical Theory, Models and Computational Methods program in the Chemistry Division to develop and implement theoretical methods enabling the first-principles calculation and interpretation of two classes of time-resolved spectroscopic signals from condensed molecular systems. In one area, Cina and his coworkers are endeavoring to predict the results of ultrafast phase-coherent multidimensional electronic spectroscopy measurements based on the ab initio determination of resonantly coupled electronic potential energy surfaces. Progress in this direction relies on the framing and implementation of a new theory based on systematically partitioning all intra and intermolecular vibrational degrees of freedom into those that are strongly coupled to the relevant electronic transitions and those that are weakly coupled or not coupled. The other area of theoretical study involves the further development and application of a mixed quantum/semiclassical method for the simulation and interpretation of time-resolved spectroscopic signals from small molecules embedded in low-temperature crystals. An essential feature of these systems, which are under experimental study by V. Ara Apkarian and co-workers at UC-Irvine, is the existence of a small number of relatively high-frequency vibrational degrees of freedom, whose dynamics our theory treats numerically rigorously, coupled to a large number of lower-frequency vibrations amenable to semiclassical approximation.
This work has a broader impact through the education and training of graduate and undergraduate students to frame and solve complex theoretical and computational problems in collaboration with experimental investigators. Scientific impacts include the development of computational tools applicable to significant problems of widespread interest in molecular science. Both aspects of our theoretical research have the potential to contribute to progress in the areas of natural and artificial photo-synthetic energy harvesting, and molecule-based quantum information processing.
