Theory of the optical spatial separation of racemic mixtures of chiral molecules

We propose a practical way of spatially separating a ("racemic") mixture of left-handed (L) and right-handed (R) chiral molecules using optically induced forces. The enantioselectivity of the method emanates from the sign difference between the n <-> m electric-dipole matrix elements of enantiomers of opposite handedness, and the, uniquely chiral, "cyclic adiabatic passage" laser configuration. The combination of these two factors is shown to cause considerable differences in the magnitude and direction of the optically induced forces as felt by enantiomers of opposite handedness. Two arrangements, tested by performing quantum wave packet propagation and classical trajectories, are suggested. Both arrangements involve the intracavity interaction of the racemic mixture with three, partially overlapping, cw laser beams. The first arrangement is composed of trapped molecules at 1 mK interacting with standing wave lasers. The second configuration uses a tightly skimmed molecular beam of a racemic mixture, forming one arm of a four-sided cavity, intersecting at a small angle the three laser beams. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3429884]