Coherently controlled photochemistry

Looking ahead, coherent laser pulses covering the complete spectral range of valence bond excitation from the UV to the IR spectral region are becoming available (see, e.g., [119]), and we expect SPODS to increase in importance in coherently controlled photochemistry with applications ranging from reaction control within molecules up to discrimination between different molecules in a mixture and laser-based quantum information technologies. 

My years of cooperation with Moshe at the Weizmann Institute preceded his brilliant work on coherent control. However, the qualities that led him to his highlight work were all there the sharpness of his thinking, his grasp of formal theory, and the insights into experimental implications. My choice of photochemistry as the topic of my contribution was influenced by his long-term interest in photodissociation and the fact that we had cooperated, among other topics, on photochemistry at surfaces. 

The advent of fs pulse lasers recently opened new perspectives for asymmetric photochemistry. The elaboration of this field still is in the theoretical realm. Pulse sequence [125,126] and coherence [127] scenarios are set up for chiral molecular products from achiral precursors. If, for example, phosphinothiotic acid H2PO(SH) molecules are preoriented, which can be effected by laser action, and a special sequence of cpl pulses is used, then the theoretical prediction is that the l enantiomer is transformed to the r enantiomer, but the reverse process is suppressed and vice versa for a different pulse sequence [125]. Chapter 2 of this book is dedicated to these coherent phenomena controlling asymmetric photoreactions. 

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