We have observed infrared spectra of the CF(3)I dimer produced in a supersonic jet by matrix-isolation Fourier transform infrared spectroscopy and infrared cavity ring-down (IR-CRD) spectroscopy. In the matrix-isolation experiments, the dimer was isolated in an Ar matrix by the pulse-deposition method. The recorded spectral range covers the symmetric (nu(1)) and doubly degenerate (nu(4)) C-F stretching regions. From the concentration dependence of the matrix-isolation spectra we have assigned one dimer band for each fundamental region. It was not easy to identify the dimer band for the nu(4) band because of the multiplet feature of the monomeric nu(4) band caused by the site symmetry breaking. The spectra of (CF(3)I)(2) in the nu(4) band region were thus also measured in the gas phase by IR-CRD spectroscopy, where we detected two dimer bands. Comparing the observed band positions with the results of quantum chemical calculations, we have assigned the observed dimer bands to the head-to-head isomer. The structure of (CF(3)I)(2) and its photochemical implications are discussed, in comparison with methyl iodide dimer reported previously [Ito et al., Chem. Phys. Lett. 343, 185 (2001)].
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Phys Chem Chem Phys
July 2023
I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany.
The ro-vibrational and pure rotational spectra of the linear ion HCO have been investigated in a 4 K cryogenic ion trap instrument. For this, a novel action spectroscopic technique, called leak-out-spectroscopy (LOS, Schmid , 2022, , 8111), has been utilized and characterized. In total, 45 ro-vibrational transitions within the fundamental band of the C-H stretching mode were measured with a band center at 3237.
View Article and Find Full Text PDFPhys Chem Chem Phys
March 2023
Department of Physics, Umeå University, Umeå, Sweden.
Brominated organic compounds are toxic ocean-derived trace gases that affect the oxidation capacity of the atmosphere and contribute to its bromine burden. Quantitative spectroscopic detection of these gases is limited by the lack of accurate absorption cross-section data as well as rigorous spectroscopic models. This work presents measurements of high-resolution spectra of dibromomethane, CHBr, from 2960 cm to 3120 cm by two optical frequency comb-based methods, Fourier transform spectroscopy and a spatially dispersive method based on a virtually imaged phased array.
View Article and Find Full Text PDFMolecules
October 2022
Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, 630090 Novosibirsk, Russia.
The present work applied the methods of density functional theory and the van der Waals interaction PBE + D3(BJ) on the basis of localized orbitals of the CRYSTAL17 package. It featured the effect of interactions between structural elements of fluorocarbonates ABCOF (A: K, Rb, Cs; B: Mg, Ca, Sr, Zn, Cd) on their elastic and vibrational properties. The hexagonal structures proved to consist of alternating ···B-CO··· and ···A-F··· layers in planes , interconnected along axis by infinite chains ···F-B-F···, where cations formed polyhedra AOF and BOF.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
October 2022
Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, D - 38106 Braunschweig, Germany. Electronic address:
High resolution infrared spectra of CHD were recorded in the region of 550-1950 cm with a Bruker IFS125 HR Fourier transform infrared spectrometers and rotational structures of the five lowest strongly interacting ν, ν,ν,ν and ν bands were analyzed. The number of about 28000 transitions (4200/6800/5600/5000/6400 for the bands ν,ν,ν,ν and ν) with J = 40 and K = 20 were assigned to these five bands. The weighted fit of 3990 upper energy values obtained from the experimentally recorded transitions was made with a Hamiltonian which takes into account resonance interactions between all studied bands as well as with the sixth ν band which was considered in this case as a "dark" one.
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December 2021
Laboratory of Ecological Instrumentation, Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch of the Russian Academy of Sciences, 634055 Tomsk, Russia.
In this work, the effect of nitrogen and carbon dioxide on the depolarization ratio of the ν band of methane in the pressure range of 0.1-5 MPa is studied. A high-sensitivity single-pass Raman spectrometer was used to obtain accurate results.
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