Chiral dissociation dynamics of molecular ratchets: Preferential senses of rotary motion in microscopic systems

Classical trajectory calculations are used to study the origin of chiral dynamics in the dissociation of structurally chiral molecules. A ratchet torsional potential about the chemical bond to be broken produces a net preference for one sense of product rotation about the recoil velocity vector. The dynamical chirality of these helical product trajectories is quantified using body-fixed bipolar moments that can be measured in gas-phase-photodissociation experiments. It is shown that the chiral dynamics is generated in the exit channel as the dissociation dynamics becomes irreversible, and is greatly accentuated by a late barrier to the dissociation reaction. [S1050-2947(98)06105-8].