196,770 research outputs found
LINE SHIFTS IN ROTATIONAL SPECTRA OF POLYATOMIC CHIRAL MOLECULES CAUSED BY THE PARITY VIOLATING ELECTROWEAK INTERACTION
No full textT.~D. Lee, C.~N. Yang, Phys. Rev., {\bf 104M. Quack, Angew. Chem. Intl. Ed., {\bf 28M. Quack, J. Stohner, Phys. Rev. Lett., {\bf 84J. Stohner, M. Quack, to be publishedAuthor Institution: ZHAW Zurich University for Applied Sciences; ICBC, Reidbach T, CH 8820 Wadenswil, Switzerland; [email protected].; ETH Zurich, Physical Chemistry, CH 8093 Zurich, SwitzerlandAre findings in high-energy physics of any importance in molecular spectroscopy ? The answer is clearly `yes'. Energies of enantiomers were considered as exactly equal in an achiral environment, e.g. the gas phase. Today, however, it is well known that this is not valid. The violation of mirror-image symmetry (suggested theoretically and confirmed experimentally in 1956/57), 254 (1956); C.~S. Wu, E.~Ambler, R.~W. Hayward, D.~D. Hoppes, R.~P. Hudson, Phys. Rev., {\bf 105}, 1413 (1957)} was established in the field of nuclear, high-energy, and atomic physics since then, and it is also the cause for a non-zero energy difference between enantiomers. We expect today that the violation of mirror-image symmetry (parity violation) influences chemistry of chiral molecules as well as their spectroscopy., 571 (1989); Angew. Chem. Intl. Ed., {\bf 41}, 4618 (2002); M.~Quack, J.~Stohner, Chimia, {\bf 59}, 530 (2005); M. Quack, J. Stohner, M. Willeke, Ann Rev. Phys. Chem. {\bf 59}, 741 (2008)} Progress has been made in the quantitative theoretical prediction of possible spectroscopic signatures of molecular parity violation. The experimental confirmation of parity violation in chiral molecules is, however, still open. Theoretical studies are helpful for the planning and important for a detailed analysis of rovibrational and tunneling spectra of chiral molecules. We report results on frequency shifts in rotational, vibrational and tunneling spectra of some selected chiral molecules which are studied in our group., 3807 (2000); M.~Quack, J.~Stohner, J.~Chem. Phys., {\bf 119}, 11228 (2003); J. Stohner, Int. J. Mass Spectrometry {\bf 233}, 385 (2004); M. Gottselig, M. Quack, J. Stohner, M. Willeke, Int. J. Mass Spectrometry {\bf 233}, 373 (2004); R. Berger, G. Laubender, M. Quack, A. Sieben, J. Stohner, M. Willeke, Angew. Chem. Intl. Ed., {\bf 44}, 3623 (2005)} If time permits, we shall also discuss critically some recent claims of experimental observations of molecular parity violation in condensed phase systems
High-resolution gigahertz and terahertz spectroscopy of the isotopically chiral molecule Trans-2,3-dideutero-oxirane(c-chd-chdo)
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Previous issue date: 22We report the observation and assignment of the rotational spectra of the isotopically chiral molecule, trans-2,3-dideutero-oxirane (c-CHD-CHDO) measured in the Gigahertz range of 62-110 GHz and in the Terahertz range, 25-80 \wn (instrumental resolution of 0.00052 \wn). Normal oxirane (c-CHO) has been detected by astrophysical spectroscopy in space.\footnote{J. E. Dickens, et al., \emph{ApJ}, \textbf{1997}, 489, 753; M. Ikeda, et al., \emph{ApJ}, \textbf{2001}, 560, 792; J. M. Lykke, et al., \emph{A\&A},\textbf{2017}, 597, A53.}A small number of lines of trans-2,3-dideutero-oxirane had been previously analyzed in the microwave region\footnote{C. Hirose, \emph{Bull. Chem. Soc. Jap.}, \textbf{1974}, 47, 1311.} up to 70 GHz. We have recently \footnote{S. Albert, Z. Chen, K. Keppler, Ph. Lerch, M. Quack, V. Schurig, O. Trapp, \emph{Phys.Chem.Chem.Phys.}, \textbf{2019}, 21, 3669} measured and successfully analyzed the rotational spectrum of monodeutero-oxirane between 65 and 119 GHz using our GHz spectrometer \footnote{M. Suter, M. Quack, \emph{Appl. Opt.}, \textbf{2015}, 54 (14), 4417; S. Albert, Z. Chen, C. Fabri, Ph. Lerch, R. Prentner, M. Quack, \emph{Mol. Phys.}, \textbf{2016}, 114, 2751.}, and in the 0.75 to 2.5 THz range measured with our FTIR setup \footnote{S. Albert, Ph. Lerch, M. Quack, \emph{ChemPhysChem}, \textbf{2013}, 14, 3204; S. Albert, K. K. Albert, Ph. Lerch, M. Quack, \emph{Faraday Discuss.}, \textbf{2011}, 150, 71.} at the Swiss Light Source.In the current work, we were able to assign and analyze more than 2500 rotational transitions of the vibronic ground state of trans-2,3-dideutero-oxirane up to J=65. The molecule is also of interest in the context of molecular parity violation, similar to the related molecule fluoro-oxirane \footnote{H. Hollenstein, D. Luckhaus, J. Pochert, M. Quack, G. Seyfang, \emph{Angew. Chemie}, \textbf{1997}, 109 (1,2), 136; R. Berger, M. Quack, J. Stohner, \emph{Angew. Chem. Intl. Ed.}, \textbf{2001}, 40, 1667.}. Our results are important in relation to isotopic chirality and parity violation\footnote{M. Quack, \emph{Fundamental Symmetries and Symmetry Violations from High Resolution Spectroscopy}, in \emph{Handbook of High-resolution Spectroscopy}, M. Quack and F. Merkt eds. , Vol.1 , pp. 659-722 Wiley, Chichester \textbf{2011}}, and to the possible astrophysical observation of this molecule
High Resolution Infrared Spectroscopy Of Cyano-oxirane (c-c<sub>2</sub>h<sub>3</sub>ocn)
No full text"Oxiranecarbonitrile (cyano-oxirane, c-CHOCN) is of interest as a possible chiral precursor molecule of evolution\footnote{M. Bolli, R. Micura, A. Eschenmoser, \emph{Chem. Biol.}, \textbf{1997}, 4, 309 (and refs. cited therein).}. We have calculated parity violation in this molecule in view of possible experiments and biomolecular homochirality\footnote{R. Berger, M. Quack, G. Tschumper, \emph{Helv. Chim. Acta.}, \textbf{2000}, 83, 1919; M. Quack, \emph{Chem. Phys. Lett.} \textbf{1986}, 132, 147; M. Quack, \emph{Angew. Chem. Intl. Ed.}, \textbf{2002}, 41, 4618.}. Its spectrum has been investigated in the millimeter, submillimeter\footnote{M. Behnke, I. Medvedev, M. Winnewisser, F. C. De Lucia, and E. Herbst, \emph{ApJ. Supplement Series}, \textbf{2004}, 152, 97.}
and terahertz\footnote{S. Albert, Ph. Lerch, K. Keppler and M. Quack, \emph{Proceedings of the XX. Symposium on Atomic, Cluster and Surface Physics 2016, (SASP 2016)}, Innsbruck University Press (2016), pp. 165-168 (and refs. cited therein).} regions. We have recorded its infrared spectrum at 295K with resolution 0.0011 \wn using the Zurich Prototype ZP 2001 FTIR spectrometer \footnote{S. Albert, K. Albert and M. Quack, \emph{Trends in Optics and Photonics}, \textbf{2003}, 84, 177; ""Handbook,"" Vol. 2, pp. 965-1019 (see also \textit{f}).}. We report here the results of the rovibrational analysis transitions associated with the \nub{12} (915.3 \wn) and \nub{13} (848.2 \wn) fundamentals using a Watson Hamiltonian and the WANG program\footnote{D. Luckhaus and M. Quack, \emph{Mol. Phys.}, \textbf{1989}, 68, 745; S. Albert, K. Keppler Albert, H. Hollenstein, C. Manca Tanner, M. Quack in ""Handbook of High-Resolution Spectroscopy,"" M. Quack and F. Merkt, Eds., 2011, Vol. 1, Chapter 3, pp. 117-173, Wiley, Chichester.}, including molecular parameters and ground state energies from our work in the THz region. Simulations performed using the parameters reproduce the observed spectrum well. The results are discussed in relation to astrophysical spectroscopic searches and the evolution of biomolecular homochirality\footnote{M. Quack, \emph{Adv. Chem. Phys.}, \textbf{2014}, 157, 249 (and refs. cited therein); M. Quack and G. Seyfang, in ""Molecular Spectroscopy and Quantum Dynamics,"" R. Marquardt and M. Quack, Eds., 2020, Ch. 7, pp. 231-282, Elsevier, Amsterdam, see also www.ir.ETHz.CH}."Made available in DSpace on 2021-09-24T21:08:48Z (GMT). No. of bitstreams: 2
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Previous issue date: 2021-06-2
Parity Violation in Chiral Molecules: From Theory towards Spectroscopic Experiment and the Evolution of Biomolecular Homochirality
No full textWe shall start with an introductory discussion of three fundamental questions relating physics to molecular quantum dynamics and stereochemistry.
(i) To what extent are the fundamental symmetries and conservation laws of physics and their violations reflected in molecular quantum dynamics and spectroscopy, in general?
(ii) How important is parity violation for the quantum dynamics and spectroscopy of chiral molecules, in particular?
(iii) How important is parity violation for biomolecular homochirality, i.e. the quasi exclusive preference of L-amino acids and D-sugars in the biopolymers of life (proteins and DNA)?
The observation of biomolecular homochirality can be considered as a quasi-fossil of the evolution of life [1], the interpretation of which has been an open question for more than a century, with numerous related hypotheses, but no definitive answers. We shall briefly discuss the current status and the relation to the other two questions.
The discovery of parity violation led to important developments of physics in the 20th century and is understood within the standard model of particle physics, SMPP. For molecular stereochemistry it leads to the surprising prediction of a small energy difference D of the ground state energies of the enantiomers of chiral molecules, corresponding to a small reaction enthalpy for the stereomutation between the R and S enantiomers [2].This reaction enthalpy would be exactly zero by symmetry with exact parity conservation. Theory predicts D to be in the sub-femto eV range, typically, depending on the molecule (about D= 100 aeV for ClSSCl or CHFClBr, corresponding to a reaction enthalpy of about 10 pJ/mol). We have outlined three decades ago, how this small energy difference D might by measured by spectroscopic experiment [3], and recent progress indicates that experiment might be successful in the near future [4-8]. We shall discuss the current status of our experiments including alternatives pursued in other groups and the possible consequences for our understanding of molecular and biomolecular chirality.For background reading see [1-7].
1. M. Quack, Adv. Chem. Phys., 2014, 157, 249-290, Chapter 18.
2. M. Quack, Fundamental Symmetries and Symmetry Violations from High Resolution Spectroscopy, in Handbook of High Resolution Spectroscopy, Vol. 1, Chapt. 18, pp. 659-722 (Eds.: M. Quack, F. Merkt), Wiley, Chichester, New York, 2011
3. M. Quack, Chem. Phys. Lett., 1986, 132, 147-153.
4. P. Dietiker, E. Miloglyadov, M. Quack, A. Schneider, G. Seyfang, J. Chem. Phys., 2015, 143, 244305, (and references cited therein).
5. R.Prentner, M. Quack, J. Stohner, M. Willeke, J. Phys. Chem. A, 2015, 119, 12805-22.
6. C. Fábri, Ľ. Horný, M. Quack, ChemPhysChem, 2015, 16, 3584–3589.
7. S. Albert, I. Bolotova, Z. Chen, C. Fábri, L. Horný, M. Quack, G. Seyfang, D. Zindel, Phys. Chem. Chem. Phys., 2016, 18, 21976-21993. A.Albert, F.Arn,I.Bolotova,Z.Chen, C.Fabri, G.Grassi, P.Lerch, M.Quack, G.Seyfang, A.Wokaun, D. Zindel, J.Phys.Chem. Lett. 2016, 7, 3847-385
High Resolution Infrared Spectroscopy Of Aziridine-2-carbonitrile (c3h4n2)
No full textMolecular parity violation has been critically discussed in relation to biomolecular homochirality in the early evolution of life
\footnote{M. Quack, , 41(24), 4618; , 157, 249, www.ir.ETHz.CH.}. In this context molecules of potential importance for prebiotic chemistry like the small, chiral three-membered heterocyclic molecule aziridine-2-carbonitrile (2-cyanoaziridine) are of interest \footnote{A. Eschenmoser and E. Loewenthal, , 21, 1.}. Indeed, this molecule has been previously examined \footnote{S. Drenkard, J. Ferris, and A. Eschenmoser, , 73, 1373.} and the parity violating energy difference between the enantiomers in their ground state has also been calculated \footnote{R. Berger, M. Quack and G.S. Tschumper, , 83(8), 1919.}. Molecular parameters for the ground state of this molecule are available from earlier microwave studies \footnote{R.D. Brown, P.D. Godfrey, and A.L. Ottrey, , 82, 73.}, and its conformations have been examined by theory \footnote{G.S. Tschumper, , 114(1), 225.}.
Here we report initial results of a high resolution spectroscopic study of cyanoaziridine, carried out at room temperature with an instrumental resolution of 0.0011 \wn \ in the 800-1000 \wn \ region using the Bruker IFS125 Zurich Prototype (ZP2001) Fourier transform spectrometer \footnote{S. Albert, K. Albert and M. Quack, , 84, 177; S. Albert, K. Keppler Albert, M. Quack, Ch. 26, Handbook of High-Resolution Spectroscopy, Vol. 2, p. 965--1019, M. Quack, F. Merkt, Eds., Wiley, Chichester (2011).}.
Transitions in the \nub{15} and \nub{16} bands have been assigned, and molecular parameters have been determined using the Watson Hamiltonian. Simulations performed using these parameters reproduce the observed spectra well. The results are discussed in relation to astrophysical spectroscopy and recent efforts on parity violation in chiral molecules \footnote{M. Quack and G. Seyfang,“Tunnelling and Parity Violation in Chiral and Achiral Molecules: Theory and High-Resolution Spectroscopy,” Chapter 6, Tunnelling in Molecules: Nuclear Quantum Effects from Bio to Physical Chemistry, p.192--244, J. Kästner, S. Kozuch, Eds., RSC, Cambridge (2020), ISBN: 978-1-78801-870-8; M. Quack, G. Seyfang, G. Wichmann, , 81, 51--104.}
High-resolution Gigahertz And Terahertz Spectroscopy Of The Isotopically Chiral Molecule Trans-2,3-dideutero-oxirane(c-chd-chdo)
No full textWe report the observation and assignment of the rotational spectra of the isotopically chiral molecule, trans-2,3-dideutero-oxirane (c-CHD-CHDO) measured in the gigahertz range of 62-110 GHz and in the terahertz range, 25-80 \wn (instrumental resolution of 0.00052 \wn). Normal oxirane (c-CHO) has been detected by astrophysical spectroscopy in space.\footnote{J. E. Dickens, et al., \emph{ApJ}, \textbf{1997}, 489, 753; M. Ikeda, et al., \emph{ApJ}, \textbf{2001}, 560, 792; J. M. Lykke, et al., \emph{A\&A},\textbf{2017}, 597, A53.}A small number of lines of trans-2,3-dideutero-oxirane had been previously analyzed in the microwave region\footnote{C. Hirose, \emph{Bull. Chem. Soc. Jap.}, \textbf{1974}, 47, 1311.} up to 70 GHz. We have recently \footnote{S. Albert, Z. Chen, K. Keppler, Ph. Lerch, M. Quack, V. Schurig, O. Trapp, \emph{Phys.Chem.Chem.Phys.}, \textbf{2019}, 21, 3669} measured and successfully analyzed the rotational spectrum of monodeutero-oxirane between 65 and 119 GHz using our GHz spectrometer,\footnote{M. Suter, M. Quack, \emph{Appl. Opt.}, \textbf{2015}, 54 (14), 4417; S. Albert, Z. Chen, C. Fabri, Ph. Lerch, R. Prentner, M. Quack, \emph{Mol. Phys.}, \textbf{2016}, 114, 2751.} and in the 0.75 to 2.5 THz range measured with our FTIR setup \footnote{S. Albert, Ph. Lerch, M. Quack, \emph{ChemPhysChem}, \textbf{2013}, 14, 3204; S. Albert, K. K. Albert, Ph. Lerch, M. Quack, \emph{Faraday Discuss.}, \textbf{2011}, 150, 71.} at the Swiss Light Source.In the current work, we were able to assign and analyze more than 2500 rotational transitions of the vibronic ground state of trans-2,3-dideutero-oxirane up to J=65. The molecule is also of interest in the context of molecular parity violation, similar to the related molecules.\footnote{M. Quack and G. Seyfang, \emph{Tunnelling and parity violation in chiral and achiral molecules}, ch.6 in \emph{Tunnelling in Molecules}, J.Kaestner and S. Kozuch eds.,pp 192-244, RSC publishing, Cambridge \textbf{2020}, and references cited therein.} Our results are important in relation to isotopic chirality and parity violation,\footnote{M. Quack, \emph{Fundamental Symmetries and Symmetry Violations from High Resolution Spectroscopy}, in \emph{Handbook of High-resolution Spectroscopy}, M. Quack and F. Merkt eds. , Vol.1 , pp. 659-722, Wiley, Chichester \textbf{2011}.} and to the possible astrophysical observation of this molecule.Made available in DSpace on 2021-09-24T21:08:48Z (GMT). No. of bitstreams: 2
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Previous issue date: 2021-06-2
A combined gigahertz and terahertz synchrotron-based Fourier transform infrared spectroscopic investigation of ortho-D-phenol
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Previous issue date: 6Tunneling switching is a fundamental phenomenon of interest in molecular quantum dynamics including also chiral molecules and parity violation.footnote{M. Quack , textit{Fundamental Symmetries and Symmetry Violations from High-resolution Spectroscopy}, textit{Handbook of High Resolution Spectroscopy, M. Quack and F. Merkt eds.},John Wiley & Sons Ltd, Chichester, New York, 2001, vol. 1, ch. 18, pp. 659-722.}footnote{R. Prentner, M. Quack, J. Stohner and M. Willeke, textit{J. Phys. Chem. A} textbf{119}, 12805-12822 (2015).}footnote {S. Albert, Z. Chen, C. F'{a}bri, R. Prentner M. Quack and D. Zindel, paper at this meeting.} Deuterated phenols have been identified as prototypical achrial candidates.footnote{S. Albert, Ph. Lerch, R. Prentner and M. Quack, textit{Angew. Chem. Int. Ed.} textbf{52}, 346-349 (2013).} We report the high resolution spectroscopic investigation of the ortho-D-phenol in the GHz and THz ranges following our recent discovery of tunneling switching in its isotopomer meta-D-phenol.footnote{label{myfootnote}S. Albert, Z. Chen, C. F'{a}bri,P. Lerch, R. Prentner and M. Quack, emph{Mol.Phys.} textbf{114}, 2751-2768 (2016) and emph{71st International Symposium on Molecular Spectroscopy}, Urbana-Champaign, USA, June 20-24, Talk FE04 (2016).} Here we report new results on ortho-D-phenol.The pure rotational spectra were recorded in the range of 72-117 GHz and assigned to the syn- and anti- structures in the ground and the first excited torsional states. Specific torsional states were assigned based on a comparison of experimental rotational constants with the quasiadiabatic channel reaction path Hamiltonian (RPH) calculations. The torsional fundamental at ~308 cm and the first hot band at 275 cm were subsequently assigned. The analyses of pure rotational and rovibrational spectra shall be discussed in detail in relation to possible tunneling switching
High resolution infrared spectroscopy of cyano-oxirane (c-c2h3ocn)
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Previous issue date: 23Oxiranecarbonitrile (cyano-oxirane, c-CHOCN) is of interest as a possible chiral precursor molecule of evolution\footnote{M. Bolli, R. Micura, A. Eschenmoser, \emph{Chem. Biol.}, \textbf{1997}, 4, 309 (and refs. cited therein).}. We have calculated parity violation in this molecule\footnote{R. Berger, M. Quack, G. Tschumper, \emph{Helv. Chim. Acta.}, \textbf{2000}, 83, 1919.} in view of possible experiments and biomolecular homochirality\footnote{M. Quack, \emph{Chem. Phys. Lett.} \textbf{1986}, 132, 147; M. Quack, \emph{Angew. Chem. Intl. Ed.}, \textbf{2002}, 41, 4618.}. The spectrum of the molecule has been investigated in the millimeter, submillimeter\footnote{M. Behnke, I. Medvedev, M. Winnewisser, F. C. De Lucia, and E. Herbst, \emph{ApJ. Supplement Series}, \textbf{2004}, 152, 97.}
and terahertz\footnote{S. Albert, Ph. Lerch, K. Keppler and M. Quack, \emph{Proceedings of the XX. Symposium on Atomic, Cluster and Surface Physics 2016, (SASP 2016)}, Innsbruck University Press (2016), pp. 165-168 (and refs. cited therein).} regions. Here we report high resolution (0.0011 \wn) measurements of the infrared spectrum of this molecule at room temperature using the Zurich Prototype ZP 2001 FTIR Spectrometer, and a rovibrational analysis of about two thousand transitions associated with the \nub{12} (915.3 \wn) and \nub{13} (848.2 \wn) fundamentals using a Watson Hamiltonian and the WANG program\footnote{D. Luckhaus and M. Quack, \emph{Mol. Phys.}, \textbf{1989}, 68, 745; S. Albert, K. Keppler Albert, H. Hollenstein, C. Manca Tanner, M. Quack in "Handbook of High Resolution Spectroscopy," M. Quack and F. Merkt, Eds., 2011, Vol. 1, Chapter 3, pp. 117-173, Wiley, Chichester.}, including also molecular parameters and ground state energies from our work in the THz region. Accurate spectroscopic parameters were obtained. The results are discussed in relation to astrophysical spectroscopic searches and the evolution of biomolecular homochirality\footnote{M. Quack, \emph{Adv. Chem. Phys.}, \textbf{2014}, 157, 249.}
The gigahertz and terahertz spectrum of mono-deuterated oxirane (c-C2H3DO)
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Previous issue date: 6The rotational spectrum of the chiral mono-deuterated oxirane c-CHDO, an isotopomer of oxirane (ethylenoxide), of which the normal isotopomer has already been detected in interstellar clouds, was measured in the ranges 78 to 108 GHz and 25 to 70 cm. Thus one can expect that c-CHDO will be detectable in space in the future given the current accurate laboratory data.c-CHDO is also of interest as a simple prototypical molecule for isotopic chirality and parity violation.footnote{M. Quack, textit{Angew. Chem. Int. Ed.} textbf{28}, 571-586 (1989).}footnote{M. Quack , textit{Fundamental Symmetries and Symmetry Violations from High-resolution Spectroscopy}, textit{Handbook of High Resolution Spectroscopy, M. Quack and F. Merkt eds.},John Wiley & Sons Ltd, Chichester, New York, 2001, vol. 1, ch. 18, pp. 659-722.}footnote{R. Berger, G. Laubender, M. Quack, A. Sieben, J. Stohner and M. Willeke, textit{Angew. Chem. Int. Ed.} textbf{44}, 3623-3626 (2005).}footnote {S. Albert, I. Bolotova, Z. Chen, C. F'{a}bri, L. Horn'{y}, M. Quack, G. Seyfang and D. Zindel, textit{Phys.Chem.Chem.Phys.}textbf{18}, 21976-21993 (2016).} The Zurich GHz spectrometer and a high resolution FTIR interferometer using synchrotron radiation was used for the THz spectrum.footnote{S. Albert, I. Bolotova, Z. Chen, C. F'{a}bri, L. Horn'{y}, M. Quack, G. Seyfang and D. Zindel,Proceedings of the 20th Symposium on Atomic, Cluster and Surface Physics (SASP 2016), Innsbruck University Press, 2016, pp. 127-130, ISBN:978-3-903122-04-8. and to be published.}footnote {S. Albert, F. Arn, I. Bolotova, Z. Chen, C. F'{a}bri, G. Grassi, Ph. Lerch, M. Quack, G. Seyfang, A. Wokaun and D. Zindel, textit{J.Phys.Chem.Lett},textbf{7}, 3847-3853 (2016).} Previous laboratory work on the rotational spectrum of deuterated oxirane extended only to the frequency of 45 GHz. A total of 119 transitions have been newly assigned in the GHz range (extended to 119 GHz) up to J=18 and 900 transitions in the THz region at most to J=70. The analyses of the rotational spectra shall be discussed in detail in relation to their astrophysical importance
A combined gigahertz and terahertz synchrotron-based fourier transform infrared (terahertz) spectroscopic investigation of meta- and ortho-d-phenol: observation of tunneling switching
No full textTunneling switching is of fundamental interest for certain experiments aiming at detecting
parity violation in chiral molecules.\footnote{M. Quack and M. Willeke, \textit{J. Phys .Chem. A} \textbf{110},
3338-3348 (2006).}\footnote{M. Quack, \textit{Adv. Chem. Phys} \textbf{157},
247-291 (2014).} A particularly intriguing recent development is
the theoretical prediction of prototypical tunneling switching in meta- and ortho-D-phenol
(CHDOH) as opposed to phenol (CHOH)\footnote{S. Albert, Ph. Lerch, R. Prentner and M. Quack, \textit{Angew. Chem. Int. Ed.} \textbf{52},
346-349 (2013).}
where only tunneling dominates the dynamics: For meta and ortho-D-phenol at low energy, tunneling
is completely suppressed due to isotopic substitution, which introduces an asymmetry in the effective potential
including zero point vibrational energy in the lowest quasiadiabatic channel. This effectively
localizes the molecular wavefunction at either the \textit{syn} or \textit{anti} structure of meta- and ortho-D-phenol. At higher torsional states of meta- and
ortho-D-phenol, tunneling becomes dominant, thus switching the dynamics to a delocalized quantum
wavefunction.The pure rotational spectra of the meta- and ortho-D-phenol were recorded between 60 and 110 GHz using an experimental setup\footnote{M. Suter and M. Quack, \textit{Appl. Opt} \textbf{54},
4417-4431 (2015).} which we have improved somewhat whereas the rotationally resolved vibrational spectra in the THz and infrared region were collected in the range of 200 to 1000 \wn using synchrotron-based FTIR spectroscopy.\footnote{S. Albert, Ph. Lerch, R. Prentner and M. Quack, \textit{68th International Symposium on Molecular Spectroscopy}, Columbus, Ohio, USA, June 17-21, paper TG09 (2013).}The detailed assignment of the new GHz spectra including excited vibrational states, whereas previously only microwave spectra of the ground state were known,\footnote{T. Pedersen, N. W. Larsen and L. Nygaard, \textit{J. Mol. Struc.} \textbf{4},
59-77 (1969).} shall be discussed, in terms of the experimental evidence demonstrating tunneling switching in the first overtone of the torsional vibration of meta-D-phenol.Made available in DSpace on 2017-01-26T21:39:04Z (GMT). No. of bitstreams: 3
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