Ab initio optimal control of open quantum systems applied to surface photochemistry

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Control of dissipative processes in quantum systems represents a severe challenge in many areas of physics and chemistry such as atmospheric chemistry, photocatalysis, and solar energy conversion. Optimal control has the potential to successfully encounter this challenge as a generally applicable strategy. The specific aim of our project which will be pursued in the current proposal for the first time in an ab initio sense, will be the control of laser induced desorption of diatomic molecules on surfaces as a fundamental elementary process. In fact, control of a photochemical reaction on a surface by ultra-short laser-pulses is much more challenging as compared to gas-phase chemical reactions since the surface can be regarded as a reservoir, which is responsible for dissipative effects such as energy relaxation and dephasing. Therefore, a faithful control scheme crucially relies on an accurate description of these quantum dissipative effects, in particular, since excitation, control, excited state nuclear dynamics and electronic relaxation take place on the same timescale. It has been shown that the Surrogate Hamiltonian approach developed by Kosloff and coworkers is ideally suited for such dynamics. For the first time, we will theoretically investigate on an ab initio level photodesorption of diatomic molecules from the photocatalytically active substrate titania including control by ultrashort laser pulses.