Sub-Hz Differential Rotational Spectroscopy of Enantiomers

Lincoln Satterthwaite,Daniel Sorensen,Greta Koumarianou,David Patterson

doi:10.3390/sym14010028

Lincoln Satterthwaite, Daniel Sorensen + Show 2 more

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https://doi.org/10.3390/sym14010028

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Journal: Symmetry	Publication Date: Dec 27, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: University of California, Santa Barbara

Abstract

We demonstrate for the first time high-precision differential microwave spectroscopy, achieving sub-Hz precision by coupling a cryogenic buffer gas cell with a tunable microwave Fabry–Perot cavity. We report statistically limited sub-Hz precision of (0.08 ± 0.72) Hz, observed between enantiopure samples of (R)-1,2-propanediol and (S)-1,2-propanediol at frequencies near 15 GHz. We confirm highly repeatable spectroscopic measurements compared to traditional pulsed-jet methods, opening up new capabilities in probing subtle molecular structural effects at the 10−10 level and providing a platform for exploring sources of systematic error in parity-violation searches. We discuss dominant systematic effects at this level and propose possible extensions of the technique for higher precision.

Highlights

Molecules have been recently added to the selection of tools to test the standard model of particle physics to its limits and beyond [1,2,3,4,5,6,7,8,9,10]
Among the fundamental forces included in the standard model is the electroweak force, which has been observed to produce parity violating (PV) effects, emerging from the exchange of virtual Z0 bosons between electrons and nuclei
There is a large benefit to employing tailor-made chiral molecules with very heavy atoms close to the chiral center [22,23], yielding a shift on the order of ∆ pv ν/ν = 10−15

Summary

Introduction

Molecules have been recently added to the selection of tools to test the standard model of particle physics to its limits and beyond [1,2,3,4,5,6,7,8,9,10]. An experimental measurement of such a shift can provide new information towards answering fundamental questions about homochirality and the origins of life [16,17,18]. This electroweak symmetry breaking is theorized to lift degeneracy between the right and left versions (enantiomers) of chiral molecules, leading to very slight energy differences in spectroscopic transitions. These differences scale with frequency and are calculated to be at the Hz to mHz level for ∼30 THz vibrational transitions and approximately a factor of 1000 smaller for microwave transitions around 20 GHz [19,20].

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