High resolution GHz and THz (FTIR) spectroscopy and theory of parity violation and tunneling for 1,2-dithiine (C₄H₄S₂) as a candidate for measuring the parity violating energy difference between enantiomers of chiral molecules

Abstract

We report high resolution spectroscopic results of 1,2-dithiine-(1,2-dithia-3,5-cyclohexadiene, C4H4S2) in the gigahertz and terahertz spectroscopic ranges and exploratory theoretical calculations of parity violation and tunneling processes in view of a possible experimental determination of the parity violating energy difference ΔpvE in this chiral molecule. Theory predicts that the parity violating energy difference between the enantiomers in their ground state (ΔpvE ≃ 1.1 × 10(-11)(hc) cm(-1)) is in principle measurable as it is much larger than the calculated tunneling splitting for the symmetrical potential ΔE± < 10(-24) (hc) cm(-1). With a planar transition state for stereomutation at about 2500 cm(-1) tunneling splitting becomes appreciable above 2300 cm(-1). This makes levels of well-defined parity accessible to parity selection by the available powerful infrared lasers and thus useful for one of the existing experimental approaches towards molecular parity violation. The new GHz spectroscopy leads to greatly improved ground state rotational parameters for 1,2-dithiine. These are used as starting points for the first successful analyses of high resolution interferometric Fourier transform infrared (FTIR, THz) spectra of the fundamentals ν17 (1308.873 cm(-1) or 39.23903 THz), ν22 (623.094 cm(-1) or 18.67989 THz) and ν3 (1544.900 cm(-1) or 46.314937 THz) for which highly accurate spectroscopic parameters are reported. The results are discussed in relation to current efforts to measure ΔpvE.

Trendbericht Physikalische Chemie 2017: Atomare und molekulare Tunnelprozesse

“…70) Beispiele sind das HOOH-analoge ClOOCl-Molekül 70,73,74) und das 1,2-Dithiin-Molekül. 75,76) Ein weiteres Beispiel ist Trisulfan. 77 72,96) Abb.…”

“…Messung der paritätsverletzenden Energieaufspaltung ∆ PV E. 72,96) 72,96) BTrendbericht Physikalische ChemieV trien der Potenziale, bei (hc)·10 −11 bis 10 −12 cm −1 (entsprechend 1 bis 0,1 feV) liegen. 70,[73][74][75][76][77] In diesen Fällen dominiert die Paritätsverletzung die Quantendynamik. 78) Die extrem kleinen Werte von Δ PV E lassen sich nach dem Schema in Abbildung 4a messen.…”

Experimental and Theoretical Investigations of Terahertz Spectra of the Structural Isomers: Mannose and Galactose

“…In recent years, terahertz experimental methods have been widely applied in detecting biological and chemical molecules such as amino acids [1][2][3], saccharides [4,5], DNA nucleobases [6], and even harmful and dangerous materials such as pesticides [7,8], narcotics [9], and explosives [10]. e reasonable explanation for these popular applications is that THz-TDS is highly sensitive to similar materials with relatively subtle differences [11]. Meanwhile, an increasing number of researches have been done, and it was found that most organic molecules in solid state have rich and distinct spectra in the frequency region among 0.1-6.0 THz [12].…”

Synchrotron-Based Highest Resolution Terahertz Spectroscopy of the ν24 Band System of 1,2-Dithiine (C4H4S2): A Candidate for Measuring the Parity Violating Energy Difference between Enantiomers of Chiral Molecules

“…The barrier for inversion by ring puckering is ∼2500 cm –1 (in wavenumbers), of appropriate magnitude. While the infrared spectra in the higher wavenumber ranges can be partly analyzed on the basis of FTIR spectra using ordinary light sources, the important lowest frequency fundamentals fall in the terahertz range ν = 5 to 8 THz (ν̃ = 165 to 284 cm –1 as summarized in Figure ), very difficult for traditional FTIR spectroscopy but accessible to highest resolution FTIR spectroscopy using synchrotron light sources as available at the Swiss Light Source (SLS). , We report here a first successful analysis of the spectra of 1,2-dithiine in this range.…”

“…The FTIR spectra of 1,2-dithiine (C 4 H 4 S 2 ) as synthesized following ref (and refs cited therein) were recorded with the ETHSLS-2009 Bruker prototype − using synchrotron radiation in the range 200 to 340 cm –1 . This prototype spectrometer has a resolution corresponding to an unapodized instrumental bandwidth of 0.00053 cm –1 (16 MHz), which is currently the highest for a FTIR spectrometer worldwide.…”