Large vibrationally induced parity violation effects in CHDBrI+

The isotopically chiral molecular ion CHDBrI+ is identified as an exceptionally promising candidate for the detection of parity violation in vibrational transitions. The largest predicted parity-violating frequency shift reaches 1.8 Hz for the hydrogen wagging mode which has a sub-Hz natural line width and its vibrational frequency auspiciously lies in the available laser range. In stark contrast to this result, the parent neutral molecule is two orders of magnitude less sensitive to parity violation. The origin of this effect is analyzed and explained. Precision vibrational spectroscopy of CHDBrI+ is feasible as it is amenable to preparation at internally low temperatures and resistant to predissociation, promoting long interrogation times (Landau et al., J. Chem. Phys., 2023, 159, 114307). The intersection of these properties in this molecular ion places the first observation of parity violation in chiral molecules within reach.

Automated summary

The isotopically chiral molecular ion CHDBrI+ is a highly promising candidate for detecting parity violation in vibrational transitions. It exhibits an exceptionally large predicted parity-violating frequency shift for the hydrogen wagging mode, which has a sub-Hz natural line width and falls within the range of available lasers. In contrast, the parent neutral molecule is significantly less sensitive to parity violation. The origin of this effect has been analyzed and explained.