A new spin on chemical reaction dynamics

Many chemical processes involve molecules with angular momentum, associated either with the spin and orbital motion of the electrons, or with the rotation of the nuclear framework of the molecule itself. Angular momentum is a vector quantity, and therefore is characterized by both magnitude and direction. The objective of the proposed research will be to develop a novel probe of angular momentum polarization (i.e. the angular distribution characterizing the direction of the angular momentum) in the products of molecular photodissociation and bimolecular reactions. The experiments are based on the laser induced fluorescence detection method, and will exploit the technique of Faraday rotation, in which a weak magnetic field is applied to the sample to induce Zeeman quantum beats in the time resolved laser fluorescence decay of the product species of interest. This should allow sensitive detection of polarization information since the information is obtained on every laser shot of the experiment. The new method will be applied to a number of prototypical photodissociation and bimolecular collisional systems.