Vibrational and rotational spectroscopy of (CD3OD)-C-13 (original) (raw)
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CCSD(T) Study of CD 3 –O–CD 3 and CH 3 –O–CD 3 Far-Infrared Spectra
The Journal of Physical Chemistry A, 2012
From a vibrationally corrected 3D potential energy surface determined with highly correlated ab initio calculations (CCSD(T)), the lowest vibrational energies of two dimethyl-ether isotopologues, 12 CH 3 -16 0-12 CD 3 (DMEd 3 ) and 12 CD 3 -16 0-12 CD 3 (DME-d 6 ), are computed variationally. The levels that can be populated at very low temperatures correspond to the COC-bending and the two methyl torsional modes. Molecular symmetry groups are used for the classification of levels and torsional splittings. DME-d 6 belongs to the G 36 group, as the most abundant isotopologue 12 CH 3 -16 0-12 CH 3 (DME-iiJ, while DME-A, is a G 18 species. Previous assignments of experimental Raman and far-infrared spectra are discussed from an effective Hamiltonian obtained after refining the ab initio parameters. Because a good agreement between calculated and experimental transition frequencies is reached, new assignments are proposed for various combination bands corresponding to the two deuterated isotopologues and for the 020 ->• 030 transition of DME-d 6 . Vibrationally corrected potential energy barriers, structural parameters, and anharmonic spectroscopic parameters are provided. For the 3N -9 neglected vibrational modes, harmonic and anharmonic fundamental frequencies are obtained using second-order perturbation theory by means of CCSD and MP2 force fields. Fermi resonances between the COC-bending and the torsional modes modify DME-d 3 intensities and the band positions of the torsional overtones.
Journal of the Optical Society of America B, 1994
High-resolution Fourier-transform spectra of the lower vibrational fundamentals of the 13CD 3 OH isotopomer of methanol are under investigation in the 800-1350-cm-1 region, including the vs in-plane CD 3 -rocking (A'), V7 CO-stretching (A'), V5 CD 3 -deformation (A'), and V4 OH-bending (A') bands. The torsion-vibration-rotation energy-level manifold for these lower modes displays numerous perturbations that are due to torsion-vibration interactions and contains a variety of features of interest in the excited-state energy-level patterns. Analyses of the bands show that there are major problems in formulating effective Hamiltonians and in determining reliable molecular constants for the excited states because of strong torsion-vibration coupling. Assignments for five far-infrared laser transition systems have been deduced; these involve the CD 3 -rocking, CO-stretching, and CD 3 -deformation states.
Electric field effects on roto-vibrational transitions of13CD3OH1
International Journal of Infrared and Millimeter Waves, 1995
We used a Stark-Optoacoustic cell and hybrid waveguide resonators to perform an Infrared and Far Infrared Stark Spectroscopy study on some transitions of 13CD3OH. Different behaviours of the transitions in the presence of a d.c. electric field were observed. The Stark splittings of six FIR laser lines ranging from 34 to 136 MHz/kVcm -I were determined. The analysis of the behaviour of the IR and FIR transitions in the presence of the external electric fields gives important and exclusive information on the levels involved in the transitions.
The Journal of Chemical Physics, 1983
We report the detection of 17 pure rotation transitions in the ground vibronic state of the CD, radical using far infrared laser magnetic resonance spectroscopy. Fitting the data using an effective rotational Hamiltonian yields values for the three rotational constants, seven centrifugal distortion constants, the three electronic spin-rotation. and two electronic spin-spin parameters. We also fit this data, and CD, v 2 band data (published separately), using the semirigid bender Hamiltonian and obtain the effective bending potential function for CD,. Combining this with previous CH, results enables us to predict the rotation bending energy levels of CHD. We also report here the detection of two further rotational transitions in the v I excited vibrational state ofCH,.
High resolution infrared spectroscopy of H12C13CD and H13C12CD: The bending states up to v4+v5=2
Journal of Molecular Spectroscopy, 2011
The high-resolution infrared spectrum of two partially deuterated isotopologues of acetylene, H 12 C 13 CD and H 13 C 12 CD, has been recorded by Fourier transform spectroscopy in the range 450-1850 cm À1 . The bending fundamental bands and a number of overtone, combination and hot bands have been identified for both isotopomers. In total, 17 vibrational bands for H 12 C 13 CD and 18 bands for H 13 C 12 CD were analyzed, involving all the l-vibrational components of the excited bending states up to v t = v 4 + v 5 = 2. The data pertaining to each molecule were analyzed together with the pure rotational transitions recorded in the millimeter-and sub-millimeter-wave frequency ranges and the m 5 m 4 band available in the literature. The model Hamiltonian adopted for the analysis takes into account the usual vibration and rotation l-type resonances. The ground state and 9 vibrationally excited states have been characterized for each isotopomer. The spectroscopic parameters obtained from the fits reproduce 1617 transitions for H 12 C 13 CD and 1613 transitions for H 13 C 12 CD, with standard deviations of the fit equal to 0.00038 cm À1 and 0.00032 cm À1 , respectively.
Continued study of the high-resolution Fourier transform spectroscopy (FTS) of the fundamental CO-stretching band of 13CD3OH has given additional insight into the far-infrared (FIR) laser emission observed when this molecule is optically pumped by a CO2 laser. Eleven IR-pump/FIR-laser transition systems are considered. Seven represent completely new assignments, while four have been presented previously but are discussed further with reference to recently reported experimental data. Ten of the assignment schemes have been rigorously checked by forming closed combination loops, and accurate FIR laser wavenumbers have been obtained. The superiority in precision of the FIR laser wavenumbers determined from FTS combination loops over those from traditional wavelength measurements is demonstrated. 569 0195-9271/93/0300-0569507.00/0 9 1993 Plenum Publishing CoJporat~on
Infrared optoacoustic spectroscopy of13CD3OD around the 10R and 10P CO2 laser lines
International Journal of Infrared and Millimeter Waves, 1996
In this work we present the results of an investigation about Doppler limited infrared absorbing transitions of the CO stretching vibrational mode of 13CD3OD by means of optoacoustic detection. This technique is an alternative, more sensitive and of higher resolution than the Fourier transform spectroscopy which is applied to this methanol isotopomer, due to the contamination problem associated with the fast exchange of OD by OH in the molecule. Using a waveguide CO2 laser of 290 MHz ttmability on each line we were able to observe 69 absorptions, most of then of large offset. The data will be useful in theoretical analysis of this sample, as well as a guide in the search for new FIR laser lines.
The vibration-rotation emission spectra of gaseous CdH2 and CdD2
The Journal of Chemical Physics, 2005
The vibration-rotation emission spectra of CdH2 and CdD2 molecules have been recorded at high resolution using a Fourier-transform spectrometer. The molecules were generated in a furnace-discharge emission source by reaction of cadmium vapor with molecular hydrogen or deuterium. The fundamental bands for the antisymmetric stretching mode (υ3) of CdH2 and CdD2 were detected at about 1771.5 and 1278.3cm−1, respectively. In addition, the 002(Σg+)–001(Σu+) and 011(Πg)–010(Πu) hot bands were observed for CdH2. Spectroscopic constants were determined for each of the 12 observed isotopologs: Cd110H2, Cd111H2, Cd112H2, Cd113H2, Cd114H2, Cd116H2, Cd110D2, Cd111D2, Cd112D2, Cd113D2, Cd114D2, and Cd116D2. The average Cd-H and Cd-D bond distances (r0) were determined to be 1.683028(10) and 1.679161(16)Å, respectively.