Limit on the Parity Nonconserving Energy Difference between the Enantiomers of a Chiral Molecule by Laser Spectroscopy

Abstract

We have developed a saturation spectroscopy experiment to test the prediction that enantiomers of chiral molecules have different spectra because of the parity violation associated with neutral currents in the weak interaction between electrons and nuclei. First experimental tests have been conducted on hyperfine components of vibration-rotation transitions of CHFClBr in the 9.3 mm spectral range. The frequencies of saturation resonances of separated enantiomers have been compared and found to be identical within 13 Hz (Dn͞n , 4.10 213 ).

High resolution spectroscopy of methyltrioxorhenium: towards the observation of parity violation in chiral molecules

“…After the pioneering work of Yamagata 1 , Rein 2 , and Gajzago and Marx 3 who first suggested that weak interaction is responsible for an energy difference in the spectrum of right-and left-handed chiral molecules, Letokhov proposed in 1975 to observe PV effects in molecules as a difference 11 After a first test on separated enantiomers of camphor in 1977 20 , the most sensitive experiments to date following Lethokov's proposal were performed around 2000 by authors of this paper. 21,22 A CO 2 laser-based spectrometer was developed to probe a bromochlorofluoromethane (CHFClBr) transition around ν ~ 30 THz (10 µm or 1000 cm -1 ), using saturated absorption laser spectroscopy. The spectrum of each enantiomer was simultaneously recorded in separate Fabry-Perot cavities, and the absorption frequencies were compared at a 5×10 -14 level.…”

An alternative route to detect parity violating energy differences through Bose–Einstein condensation of chiral molecules

“…[4][5][6][7][8][9][10][11][12][13][14] However, no conclusive energy difference has been reported, for example, in experimental spectroscopic studies of the CHBrClF molecule reaching an energy resolution of about 10 À15 eV. 15,16 The importance of this symmetry-breaking in molecules is twofold: (i) at a fundamental level, the intrinsic chiral nature which is present in some molecules should reflect the underlying interaction containing pseudoscalar magnitudes such as those appearing in the weak interaction; and (ii) it could be intimately related to the origin of homochirality, that is, the almost exclusive one-handedness of the chiral molecules found in living systems, e.g. L-amino acids and D-sugars, this being one of the most fascinating open problems which links fundamental physics with the biochemistry of life.…”

Accurate determination of the Boltzmann constant by Doppler spectroscopy: Towards a new definition of the kelvin

“…The potential for molecules to outperform precision measurements carried out on atoms, owing to their rich electronic, vibrational, rotational and hyperfine structure is becoming increasingly apparent. Molecules are now being (or have recently been) used to test fundamental symmetries such as parity [14][15][16] and time reversal (in [17], the upper limit on the size of the electron electric dipole moment -a signature of parity and time reversal if non-zero -was set using YbF molecules, a e-mail: benoit.darquie@univ-paris13.fr b Present address: Université Paul Sabatier, Université de Toulouse, LCAR, 31062 Toulouse, France EPJ Web of Conferences outperforming the previous limit set by measurements on atoms), to test the symmetrization postulate of quantum mechanics [18], to measure either absolute values of fundamental constants (electron-toproton mass ratio [19] or Boltzmann constant as discussed in this paper), or to measure their variation in time (fine structure constant [20], electron-to-proton mass ratio [21,22]). …”