Hund’s Paradox and the Collisional Stabilization of Chiral Molecules

We identify the dominant collisional decoherence mechanism which serves to stabilize and superselect the configuration states of chiral molecules. A high-energy description of this effect is compared to the results of the exact molecular scattering problem, obtained by solving the coupled-channel equations. It allows us to predict the experimental conditions for observing the collisional suppression of the tunneling dynamics between the left- and the right-handed configuration of ${\mathrm{D}}_2{\mathrm{S}}_2$ molecules.

Figure 1

Scattering cross section ${\sigma }_{\mathrm{tot}}$ (upper panel, solid line) and decoherence cross section ${\eta }_{\mathrm{tot}}$ (lower panel, solid line) for the collision of a He atom off a ground state ${\mathrm{D}}_2{\mathrm{S}}_2$ molecule, as a function of the kinetic energy $E/k_B\le 10\mathrm{K}$ on a logarithmic scale. The dashed line corresponds to (4), and the dashed-dotted line gives the high-energy behavior (5).