Femtosecond Real-Time Probing of Reactions. 15. Time-Dependent Coherent Alignment

The time evolution of product-state anisotropy, through absorption or fluorescence, is developed and compared the experimental observations for three reactions involving elementary and complex dynamics. The reactions trans-stilbene-He → trans-stilbene + He, ICN → I + CN, and Hgl_2-Hgl + I. Reagant rotation, applied torque, vibrational averaging, and dynamic axis switching are incorporated into the theoretical treatment. The is classical in approach, but it describes the experimental behavior on the femtosecond to picosecond scale, which enables one to obtain the nature of the angular momentum in the final distribution, the of the final fragments, and the geometry of the initial complex prepared.