Probing weak force-induced parity violation by high-resolution mid-infrared molecular spectroscopy

Tokunaga, S. K.; Stoeffler, Clara; Auguste, F.; Shelkovnikov, A.; Daussy, Christophe; Amy‐Klein, Anne; Chardonnet, Christian; Darquié, Benoît

doi:10.1080/00268976.2013.821186

Cited by 82 publications

(75 citation statements)

References 68 publications

(97 reference statements)

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“…The starting point for many experiments with cold molecules is the pulsed molecular beam. For example, beams of cold molecules are used to test fundamental physics (7)(8)(9)(10)(11)(12)(13)(14) and to study collisions and reactions (16)(17)(18).…”

Section: Introductionmentioning

confidence: 99%

A buffer gas beam source for short, intense and slow molecular pulses

Truppe

Hambach

Skoff

et al. 2017

Journal of Modern Optics

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Section: Introductionmentioning

confidence: 99%

A buffer gas beam source for short, intense and slow molecular pulses

Truppe

Hambach

Skoff

et al. 2017

Journal of Modern Optics

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“…For example, precise knowledge of molecular constants is required for modeling atmospheres, whether it be our own 1,2 or those found in exo-planets 3 and in the interstellar medium 4 , for studying collision physics 5,6 , and as crucial groundwork for performing fundamental physics tests 7,8,9,10,11,12,13,14,15,16,17 . One such test is the measurement of the parity-violating (PV) energy difference between opposite enantiomers of a chiral molecule, induced by the weak interaction.…”

Section: Iintroductionmentioning

confidence: 99%

Characterising molecules for fundamental physics: an accurate spectroscopic model of methyltrioxorhenium derived from new infrared and millimetre-wave measurements

Asselin

Berger

Huet

et al. 2017

Phys. Chem. Chem. Phys.

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Following our first paper about high resolution spectroscopy of methyltrioxorhenium (MTO) [Stoeffler et al. PCCP, 13, 854, (2011)], the present study reports a deeper investigation of the ground state, and Re=O antisymmetric (as) and symmetric (s) stretching excited states of both CH3 187 ReO3 and CH3 185 ReO3 isotopologues, thanks to new devices implemented within our consortium. We carry out high resolution millimeter-wave (MMW) and infrared (IR) spectroscopy in room temperature absorption cells, in a pulsed supersonic jet and in a cryogenic buffer gas cell. This collection of sensitive spectrometers enables us to probe both levels of a vibrational transition in low and room temperature gaseous environments. We thus report a new series of measurements providing particularly accurate rotational and rovibrational data for such a large and heavy organometallic molecule that is solid at room temperature.The combination of the new MMW and IR data leads to an improvement of the rovibrational model of MTO: (i) rotational spectra are extended to the 150-300 GHz range and are analyzed to characterize the ground state rotational and hyperfine structure up to J = 43 and K = 41, resulting in the significant refinement of rotational, quartic and hyperfine parameters, as well as the determination of sextic parameters and a centrifugal distortion correction to the quadrupolar hyperfine constant,(ii) rovibrational data recorded at very different temperatures (between 6 and 300 K) in the 970-1015 cm -1 range, at resolutions down to 8 MHz and frequency accuracies as high as 30 MHz (using the buffer gas technique), are used in a first step to extract more precise excited-state rotational, Coriolis and quartic parameters as well as the ground-state centrifugal distortion parameter of the 187 Re isotopologue, which isn't accessible from rotational spectroscopy alone. In a second step, taking the hyperfine structure into account, the upper state rhenium atom quadrupole coupling constant eQq' is determined from the assignment of partially hyperfine-resolved CO2 laser absorption spectra of a skimmed molecular beam.* now at National Physical Laboratory, Teddington, TW11 0LW, UK. 2 IIntroductionThere is an increasing demand for precision spectroscopy of polyatomic molecules. For example, precise knowledge of molecular constants is required for modeling atmospheres, whether it be our own 1,2 or those found in exo-planets 3 and in the interstellar medium 4 , for studying collision physics 5,6 , and as crucial groundwork for performing fundamental physics tests 7,8,9,10,11,12,13,14,15,16,17 . One such test is the measurement of the parity-violating (PV) energy difference between opposite enantiomers of a chiral molecule, induced by the weak interaction. 18 The chiral derivatives of methyltrioxorhenium (MTO) are excellent candidate species for this measurement, because calculations predict relatively large PV energy differences, and because it is possible to synthesize these molecules and bring them into the gas phase. 8,17,19,20 In...

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“…4 exhibits three isolated rovibrational lines of the ν 2 vibrational mode of 14 NH 3 . The MTO spectrum looks very different with a mean ∼ 5.5% absorption and ∼ 100 MHz wide ∼ 2% deviations as expected from the dense antisymmetric Re=O stretching mode of the molecule 3,13,31 . Both spectra were normalized by numerically correcting for the baseline.…”

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confidence: 74%

“…These species are of interest for the two precision measurements under progress in our group. The former is our molecule of choice for measuring k B , while the latter, MTO is an achiral test organometallic complex whose chiral derivatives are considered for a parity violation test 3,13,31 . The QCL is a cw-mode near-room-temperature (near-RT) single-mode DFB laser (from Alpes Lasers) tunable between 10.34 and 10.42 µm (28.76 to 29.00 THz).…”

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confidence: 99%

A widely tunable 10-μm quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy

Sow

Mejri

Tokunaga

et al. 2014

Applied Physics Letters

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We report the coherent phase-locking of a quantum cascade laser (QCL) at 10-µm to the secondary frequency standard of this spectral region, a CO 2 laser stabilized on a saturated absorption line of OsO 4 . The stability and accuracy of the standard are transferred to the QCL resulting in a line width of the order of 10 Hz, and leading to our knowledge to the narrowest QCL to date. The locked QCL is then used to perform absorption spectroscopy spanning 6 GHz of NH 3 and methyltrioxorhenium, two species of interest for applications in precision measurements.With their rich internal structure, molecules can play a decisive role in precision tests of fundamental physics. They are being used to test fundamental symmetries such as parity 1-3 or parity and time reversal 4 , to measure absolute values of fundamental constants 5-7 and their possible temporal variation [8][9][10] . Many of these experiments can be cast as measurements of resonance frequencies of molecular transitions, for which ultra-stable and accurate sources in the mid-infrared (mid-IR) are highly desirable, since most rovibrational transitions are to be found in that region.Our group has a long-standing interest in performing spectroscopic precision measurements on molecules at extreme resolutions around 10 µm 1,9,11 . We are currently working on two such measurements: the determination of the Boltzmann constant, k B , by Doppler spectroscopy of ammonia 6,12 and the first observation of parity violation by Ramsey interferometry of a beam of chiral molecules 3,13 . For these experiments, we currently use spectrometers based on custom built ultra-stable CO 2 lasers. We obtain the required metrological frequency stability and accuracy -10 Hz line width, 1 Hz stability at 1 s, accuracy of a few tens of hertz 14,15 -by stabilizing these lasers to saturated absorption lines of molecules such as OsO 4 . CO 2 lasers have a major shortcoming: a lack of tunability. They emit at CO 2 molecular resonances. An emission line is found every 30 to 50 GHz in the 9-11 µm wavelength range, and each line is tunable over about 100 MHz. Although, as in our spectrometers, this range can be extended a few gigahertz using electrooptical modulators (EOMs), this is done at the expense of power (EOMs at these wavelengths have an efficiency of 10 −4 ) and necessitates subsequent spectral filtering. Overcoming these difficulties without the loss of stability is key to enabling precision measurements in the mid-IR.One solution would be to use frequency combreferenced continuous-wave (cw) [16][17][18] or femtosecond mid-IR sources. These are based on frequency mixing in nonlinear crystals and provide absolute-frequency referencing, reasonable line widths and tunability, but are very complex and often exhibit limited power. By comparison, cw quantum cascade lasers (QCLs) are a new mature and robust technology that offer broad and continuous tuning over several hundred gigahertz at 100 mW-level powers. Several can be combined giving access to the whole mid-IR region. Recent studies of...

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Probing weak force-induced parity violation by high-resolution mid-infrared molecular spectroscopy

Cited by 82 publications

References 68 publications

A buffer gas beam source for short, intense and slow molecular pulses

A buffer gas beam source for short, intense and slow molecular pulses

Characterising molecules for fundamental physics: an accurate spectroscopic model of methyltrioxorhenium derived from new infrared and millimetre-wave measurements

A widely tunable 10-μm quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy

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