While many consider chiral enantiomers to be mirror images of each other, the
nuclear weak force is predicted to break this symmetry through parity violation (PV).
The weak force is predicted to make one enantiomer more stable than the other and
to induce small differences in their rovibrational spectra. We are developing an
experiment to measure the PV between enantiomers in chiral molecular ions.
CHDBrI + is one of the most promising candidates for PV measurements due to its
predicted large PV and its suitability for long interrogation times in an ion trap.
Moreover, it is one of the few candidates to have been synthesized, making it
experimentally accessible. In this talk, I will present the first spectral measurement of
CHDBrI + , demonstrating vibrational state-selective generation of internally cold
molecular ions. Internally cold molecular ions are an essential ingredient for
performing precision measurements. We also extract the vibrational frequency of the
CBrI-scissor mode from the spectrum. To achieve this, we employed VUV mass-
analyzed threshold ionization.
Beyond state preparation, PV measurements require efficient state detection.
Enantiomer separation is essential for proposed PV measurements that
simultaneously measure the two enantiomers. Moreover, such schemes require
vibrational-state separation to probe PV-sensitive transitions. More generally,
enantiomer separation is particularly important for the pharmaceutical industry.
Enantiomer-specific state transfer (ESST), based on microwave three-wave mixing,
has recently emerged as a promising approach for enantiomer separation. Extending
ESST to mid-infrared rovibrational transitions could reduce sensitivity to initial
thermal population and experimental systematic errors. However, the practical
implementation of rovibrational ESST schemes is hindered by the difficulty of
generating mutually phase-coherent mid-infrared lasers. We will present a scheme to
directly use a single frequency comb and a microwave field to perform ESST,
simplifying the setup by alleviating the need for mutually phase-coherent mid-infrared
lasers. Our numerical simulations demonstrate 100% enantiomer separation under
ideal conditions for multiple molecular ions, including CHDBrI + .
Both works develop experimental tools needed for future PV measurements in chiral
molecular ions.