Vibrational spectra of small organic nitriles, propionitrile and n-butyronitrile, have been investigated at high spectral resolution at the French national synchroton facility SOLEIL using Fourier-transform far-infrared spectroscopy ( <  700 cm⁻¹). The Automated Spectral Assignment Procedure (ASAP)M. A. Martin-Drumel, C. P. Endres, O. Zingsheim, T. Salomon, J. van Wijngaarden, O. Pirali, S. Gruet, F. Lewen, S. Schlemmer, M. C. McCarthy, and S. Thorwirth 2015, J. Mol. Spectrosc. 315, 72as been used for line assignement and accurate determination of rotational level energies, in particular, of the ν₂₀=1 and the ν₁₂=1 states of propionitrile. The analysis does not only confirm the applicability of the ASAP in the treatment of (dense) high-resolution infrared spectra but also reveals some of its limitations which will be discussed in some detail.

---

Footnotes:

M. A. Martin-Drumel, C. P. Endres, O. Zingsheim, T. Salomon, J. van Wijngaarden, O. Pirali, S. Gruet, F. Lewen, S. Schlemmer, M. C. McCarthy, and S. Thorwirth 2015, J. Mol. Spectrosc. 315, 72h

Vinyl alcohol has been extensively studied in both the microwaveS. Saito, Chem. Phys. Lett. 42, 3 (1976)^,M. Rodler et al., J. Am. Chem. Soc. 106, 4029 (1948)nd mid−IRY. Koga et al., J. Mol. Spec. 145, 315 (1991)^,D-L. Joo et al., J. Mol. Spec. 197, 68 (1999)pectral regions, where 9 out of 15 vibrational modes have been identified. Here we present the first far-IR spectrum of vinyl alcohol, collected below 700 cm⁻¹at the Australian Synchrotron. The high resolution (0.001 cm⁻¹) spectrum reveals the ν₁₁ and ν₁₅ fundamentals of syn-vinyl alcohol at 489 cm⁻¹and 407 cm⁻¹, in addition to two hot bands of the ν₁₅ mode at 369 cm⁻¹and 323 cm⁻¹. High J transitions in the R-branch of the ν₁₅ band were found to be perturbed by an a-axis Coriolis interaction with the nearby ν₁₁ state. The ν₁₅ torsional mode of syn-vinyl alcohol was fit using a Watson's A-reduced Hamiltonian to yield rotational, centrifugal distortion, and Coriolis coupling parameters. S. Saito, Chem. Phys. Lett. 42, 3 (1976)\end M. Rodler et al., J. Am. Chem. Soc. 106, 4029 (1948)a\end Y. Koga et al., J. Mol. Spec. 145, 315 (1991) D-L. Joo et al., J. Mol. Spec. 197, 68 (1999)s

Vinyl alcohol can exist in two rotameric forms, known as syn- and anti- vinyl alcohol, where syn is the most stable. Both rotamers have been observed in the interstellar medium towards Sagittarius B2(N) making them of particular astrophysical importanceB. E. Turner, A. J. Apponi, ApJ 561, 207 (2001) Vinyl alcohol has been subject to various spectroscopic investigations, however, the anti rotamer has only been obsvered in the microwave regionM. Rodler, J. Mol. Spec. 114, 23 (1985) We report the high resolution (0.001 cm⁻¹) FTIR spectrum of anti-vinyl alcohol collected at the infrared beamline facility of the Australian Synchrotron. Vinyl alcohol was produced via the pyrolysis of 2-chloroethanol at 900^°CD-L Joo, et al., J. Mol. Spec. 197, 68 (1999) and its far infrared spectrum reveals the presence of the strong ν₁₅ fundamental and hot band of anti-vinyl alcohol. Rotational and centrifugal distortion constants of this higher energy rotamer have since been determined for the ν₁₅ and 2ν₁₅ states, and the ground state constants have been refined. B. E. Turner, A. J. Apponi, ApJ 561, 207 (2001). M. Rodler, J. Mol. Spec. 114, 23 (1985). D-L Joo, et al., J. Mol. Spec. 197, 68 (1999),

Tunneling switching is of fundamental interest for certain experiments aiming at detecting parity violation in chiral molecules.M. Quack and M. Willeke, J. Phys .Chem. A 110, 3338-3348 (2006).^,M. Quack, Adv. Chem. Phys 157,247−291 (2014). particularly intriguing recent development isthe theoretical prediction of prototypical tunneling switching in meta− and ortho−D−phenol (C_6H_4DOH) as opposed to phenol (C_6H_5 M. Quack, Adv. Chem. Phys 157,247-291 (2014).AS. Albert, Ph. Lerch, R. Prentner and M. Quack, Angew. Chem. Int. Ed. 52,346-349 (2013).wM. Suter and M. Quack, Appl. Opt 54,4417-4431 (2015).wS. Albert, Ph. Lerch, R. Prentner and M. Quack, 68th International Symposium on Molecular Spectroscopy, Columbus, Ohio, USA, June 17-21, paper TG09 (2013).TT. Pedersen, N. W. Larsen and L. Nygaard, J. Mol. Struc. 4,59-77 (1969).s

Rotationally-resolved vibrational spectra of trimethlyene oxide (c-C₃H6O) from 650 through 1200 cm⁻¹were recorded using far infrared synchrotron radiation at the Canadian Light Source with better than 0.001 cm⁻¹resolution. The observed bands correspond to at least eight different fundamental vibrations in this region. Due to the low frequency ring puckering motion,G. Moruzzi et al., J. Mol. Spectrosc. 219, 152 (2003).he observed rovibrational pattern of each band is congested with hot-combination bands that originate in the first two excited ring puckering states (52.9 cm⁻¹, 142.6 cm⁻¹). The ongoing analysis of the strong b-type bands corresponding to asymmetric in-plane CO stretching (ν₁₀:1008 cm⁻¹)Bánhegyi et al. Spectrochim. Acta. 39A, 761 (1983).ill be discussed along with the identification of allowed Coriolis interactions arising from nearby energy levels related to in-plane CC stretching (ν₉: 940 cm⁻¹, ν₃: 1033 cm⁻¹).

---

Footnotes:

G. Moruzzi et al., J. Mol. Spectrosc. 219, 152 (2003).t Bánhegyi et al. Spectrochim. Acta. 39A, 761 (1983).w

When the electron bunches in a storage ring are sufficiently short the electrons act coherently producing radiation several orders of magnitude more intense than normal synchrotron radiation. This is referred to as Coherent Syncrotron Radiation (CSR). Due to the potential of CSR to provide a good source of Terahertz radiation for our users, the Canadian Light Source (CLS) has been researching the production and application of CSR. CSR has been produced at the CLS for many years, and has been used for a number of applications. However, resonances that permeate the spectrum at wavenumber intervals of 0.074 cm⁻¹, and are highly stable under changes in the machine setup, have hampered some experiments. Analogous resonances were predicted long ago in an idealized theory. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber. The wakefield is observed directly in the 30–110 GHz range by rf diodes. These results are consistent with observations made by the interferometer in the THz range. Also discussed will be some practical examples of the application of CSR for the study of condensed phase samples using both transmission and Photoacoustic techniques.

A new class of many-electron Auger transitions in atoms was initially proposed over 40 years agoG.N. Ogurtsov et al., Sov. Phys. Tech. Phys. 15, 1656 (1971) and V.V. Afrosimov et al., JETP Lett. 21, 249 (1975). but the first tentative evidence for its real existence was only adduced by Lee et al.I. Lee, R. Wehlitz, U. Becker and M. Ya. Amusia, J. Phys. B: At. Mol. Opt. Phys. 26, L41 (1993).n 1993, on the basis of the resonant Auger spectrum of Kr. Using a multi-electron coincidence technique with synchrotron radiation, we unambiguously showed very recently that the transition suggested by Lee et al. in Kr really does take place, but with a rather small branching ratioJ.H.D. Eland, R.J. Squibb, M. Mucke, S. Zagorodskikh, P. Linusson, and R. Feifel, New J. Phys. 17, 122001 (2015). Related inter-atomic three-electron transitions in rare gas clusters were recently predicted by Averbukh and KolorenčV. Averbukh and P. Kolorenč, Phys. Rev. Lett. 103, 183001 (2009).nd demonstrated by Ouchi et al.T. Ouchi et al., Phys. Rev. Lett. 107, 053401 (2011). From consideration of the energy levels involved it seems that the basic three-electron process could occur in molecules too, wherever a double inner-valence shell vacancy lies at a higher energy than the molecular triple ionisation onset. Experiments on CH₃F reveal for the first time the existence of this new decay pathway thereR. Feifel et al., Phys. Rev. Lett. 116, 073001 (2016). and calculations show that despite its three-electron nature, its effective oscillator strength is orders of magnitudes higher than in atoms, allowing an efficient competition with both molecular dissociation and two-electron decay channels on the ultrafast time scale. The dramatic enhancement of the molecular three-electron Auger transition can be explained in terms of a partial breakdown of the molecular orbital picture of ionisation. We predict that the collective decay pathway will be significant in a wide variety of heteroatomic molecules ionised by extreme UV and soft X-rays, particularly at Free-Electron-Lasers where double inner-shell vacancies can be created efficiently by two-photon transitions.

---

Footnotes:

G.N. Ogurtsov et al., Sov. Phys. Tech. Phys. 15, 1656 (1971) and V.V. Afrosimov et al., JETP Lett. 21, 249 (1975)., I. Lee, R. Wehlitz, U. Becker and M. Ya. Amusia, J. Phys. B: At. Mol. Opt. Phys. 26, L41 (1993).i J.H.D. Eland, R.J. Squibb, M. Mucke, S. Zagorodskikh, P. Linusson, and R. Feifel, New J. Phys. 17, 122001 (2015).. V. Averbukh and P. Kolorenč, Phys. Rev. Lett. 103, 183001 (2009).a T. Ouchi et al., Phys. Rev. Lett. 107, 053401 (2011).. R. Feifel et al., Phys. Rev. Lett. 116, 073001 (2016).,

We have analyzed multiple spectra of high purity (99.5%) normal ammonia sample recorded at room temperatures using the FT-IR and AILES beamline at Synchrotron SOLEIL, France. More than 2830 line positions and intensities are measured for the inversion-rotation and rovibrational transitions in the 50 – 660 cm⁻¹region. Quantum assignments were made for 2047 transitions from eight bands including four inversion-rotation bands (gs(a-s), ν₂(a-s), 2ν₂(a-s), and ν₄(a-s)) and four ro-vibrational bands (ν₂ – gs, 2ν₂ – gs, ν₄ – ν₂, and 2ν₂ –ν₄), as well as covering more than 300 lines of ∆K = 3 forbidden transitions. Out of the eight bands, we note that 2ν₂ – ν₄ has not been listed in the HITRAN 2012 database. The measured line positions for the assigned transitions are in an excellent agreement (typically better than 0.001 cm⁻¹) with the predictions from the empirical Hamiltonian model [S. Yu, J.C. Pearson, B.J. Drouin, et al.(2010)] in a wide range of J and K for all the eight bands. The comparison with the HITRAN 2012 database is also satisfactory, although systematic offsets are seen for transitions with high J and K and those from weak bands. However, differences of 20% or so are seen in line intensities for allowed transitions between the measurements and the model predictions, depending on the bands. We have also noticed that most of the intensity outliers in the Hamiltonian model predictions belong to transitions from gs(a-s) band. We present the final results of the FT-IR measurements of line positions and intensities, and their comparisons to the model predictions and the HITRAN 2012 database.Research described in this paper was performed at the Jet Propulsion Laboratory and California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.html:<hr /><h3>Footnotes: Research described in this paper was performed at the Jet Propulsion Laboratory and California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

Hydrogen is the most abundant element in the universe and oxygen is the third, so understanding the interaction between the two in their different forms is important to understanding astrochemical processes. The interaction between H₂ and O₂ has been explored in low energy scattering experimentsY. Kalugina, et al., Phys. Chem. Chem. Phys. 14, 16458 (2012)^,S. Chefdeville et al. Science 341, 1094 (2013)nd by far infrared synchrotron spectroscopy of the van der Waals complexH. Bunn et al. ApJ 799, 65 (2015) The far infrared spectra suggest a parallel stacked average structure with seven bound rotationally excited states. Here, we present the far infrared spectrum of HD/D_2−O_2 and the mid infrared spectrum of H_2−O_2 at 80 K, recorded at the infrared beamline facility of the Australian Synchrotron. We observed ′sharp′peaks in the mid infrared region, corresponding to the end over end rotation of H_2−O_2, that are comparatively noisier than analogous peaks in the far infrared where the synchrotron light is brightest. The larger reduced mass of HD and D_2 compared to H_2 S. Chefdeville et al. Science 341, 1094 (2013)aH. Bunn et al. ApJ 799, 65 (2015).

We report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of high-temperature and supercritical water, where spectra were measured from room temperature up to the critical temperature, and as a function of density above the critical temperature. Spectra are seen to redshift with increasing temperature, demonstrating gradual breakdown of the hydrogen bond network. Above the critical temperature, tuning the density gives direct insight into the extent of hydrogen bonding in the supercritical regime. The known gas-phase monomer spectrum can be duplicated in the low-density limit, with negligible contribution from hydrogen bonding. With increasing density, the spectrum blue shifts as small water clusters form, increasing the number of hydrogen bonds lowering the ground-state energy. The presence of vibrational structure inherent to the lowest-density gas-phase limit spectrum gradually diminishes with increasing density, giving a reasonable measure of the extent of water monomers having unperturbed electronic structure as a function of density.