What stabilizes enantiomers: parity violation or environmental decoherence? · revision history
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Accepted · first revision · record
- Title
- What stabilizes enantiomers: parity violation or environmental decoherence?
- Plain
- Quantum mechanics without the weak force says a chiral molecule's true lowest state is an equal mix of left and right forms, yet real chiral molecules stay left or right for practical eternity. Whether the weak force or the molecule's surroundings fixes the handedness is still debated for molecules where the two effects are comparable.
- Precise
- For a chiral molecule with tunneling splitting $\Delta_{+-}$ between parity eigenstates, chirality is stable if $\Delta E_{\mathrm{PV}} >> \Delta_{+-}$ (weak force dominates) or if environmental decoherence and collisions localize the state. Question: for molecules where $\Delta_{+-}$ and $\Delta E_{\mathrm{PV}}$ are comparable (proposed: ClSSCl and related axially chiral molecules), which mechanism controls the observed time evolution, and at what $\Delta_{+-} / \Delta E_{\mathrm{PV}}$ and collision rate does the crossover occur. An answer is a measured time evolution of parity or chirality in such a molecule under controlled collision rates, matched by theory.
- Settled by
- Gas-phase or molecular-beam measurement of parity-state evolution in a molecule with $\Delta_{+-}$ near $\Delta E_{\mathrm{PV}}$, at variable pressure.
- Kind
- phenomenon
- Answer type
- mechanism
- References
- (empty)
- Literature status
- partially-resolved
- Status note
- For molecules with large barriers decoherence and $\Delta E_{\mathrm{PV}}$ both explain stability; the comparable regime remains untested experimentally.
- Posed since
- 1927