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  • 11
    Electronic Resource
    Electronic Resource
    Intensity analysis of the torsional spectrum of CH3CH3 (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 3981-3988 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The far-infrared spectrum of gaseous CH3CH3 has been measured in the region of the torsional fundamental under relatively large pressure-path length conditions. Observations were made at resolutions of 0.08, 0.02, and 0.016 cm−1 and under various experimental conditions using two different Fourier transform spectrometers. In addition, a very high resolution (0.0014 cm−1) spectrum of the lowest lying degenerate fundamental ν9 was obtained. From a frequency analysis of the far-infrared spectrum and 737 lower state combination differences in ν9 and its associated hot band ν9+ν4−ν4, an improved set of torsion–rotation parameters was obtained. An intensity analysis of the torsional bands was carried out to obtain torsional dipole moments. The torsional dipole components μ⊥ and (μ(parallel)−μ⊥ ) were determined to be 9.37(70) and −31.7(2.0) μD, respectively. These experimental values are in good agreement with calculated values of μ⊥=10.13 μD and (μ(parallel)−μ⊥ )=−35.10 μD. The shape of the torsional bands can be reproduced in detail with the model adopted here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462937
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  • 12
    Electronic Resource
    Electronic Resource
    Spectra of the rare gas hydrides. IV. Three new bands of argon deuteride involving a low-lying "p'' Rydberg state (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 7093-7110 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Three fairly strong emission bands of ArD at 6100, 6900, and 10 200 cm−1 have been studied at high resolution. They show very different structures: the first exhibits only Q-form branches, the second P, R, O, and S-form branches, and the third Q, S, and O-form branches. The rotational analysis of each of these bands is not trivial, mainly because the upper state of the first which proved to be also the lower state of the second and third is strongly affected by l uncoupling [i.e., transition to Hund's case (d)] and as a result the usual method of combination differences cannot be applied in their analysis. However, more sophisticated combination differences have been found between the three bands which lead to unambiguous assignments of rotational quantum numbers and thus to rotational constants. It was found that the upper state of the 6100 cm−1 band can be most conveniently represented as a p(2Σ,2Π) complex. This assumption, together with the theoretical selection rules for such a case, led to a full understanding of the structure of the three bands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.463535
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  • 13
    Electronic Resource
    Electronic Resource
    Confirmation of far infrared laser assignments from CH3-deformation and CH3-rocking states of optically pumped methanol (1988)
    Springer
    Applied physics 47 (1988), S. 319-324 
    Details
    ISSN: 1432-0649
    Keywords: 33.20E ; 42.55H
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High-resolution Fourier transform spectroscopy has been applied to confirm previously proposed assignments for nine far infrared (FIR) laser lines from the CH3-deformation state of CH3OH and one line from the CH3-rocking state. Accurate frequencies are deduced for the observed and other predicted FIR laser transitions. FIR torsional branch frequencies in the ground state which were used in the confirmation are presented. Comments are also made on the OH-bending mode of CH3OH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716093
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  • 14
    Electronic Resource
    Electronic Resource
    High-resolution far-infrared spectroscopy of C-13 methanol (1988)
    Springer
    International journal of infrared and millimeter waves 9 (1988), S. 1119-1140 
    Details
    ISSN: 1572-9559
    Keywords: Far-infrared (FIR) spectra ; methanol ; torsion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The high-resolution far-infrared (FIR) Fourier transform spectrum of13CH3OH has been studied from 25–350 cm−1, andb-typerR-branches in the torsional ground state have been assigned. The branches have been fitted to phenomeno-logical expansion parameters, which reproduce the branch frequencies generally to well within ±0.001 cm−1. An interesting and relatively novel ΔK=4 perturbation, localized to levels around J=18, has been observed between (nτK)=(019) and (125) states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01009305
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  • 15
    Electronic Resource
    Electronic Resource
    Far infrared spectrum of CD3OH methanol from 40–220 CM−1 (1993)
    Springer
    International journal of infrared and millimeter waves 14 (1993), S. 1727-1753 
    Details
    ISSN: 1572-9559
    Keywords: Far-infrared (FIR) ; spectra ; methanol ; CD3OH ; torsion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Fourier transform far-infrared (FTFIR) spectrum of CD3OH has been obtained from 40–220 cm−1 at a resolution of 0.002 cm−1, and partially analyzed. Numerousb-type branches have been assigned in the spectrum, ranging over torsional states fromn=0 to 3. The branches have been fitted toJ(J+1) power-series energy expansions in order to obtainJ-independent branch origins. These in turn have been fitted to the torsion-rotation Hamiltonian, and improved molecular constants have been obtained for the ground vibrational state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02101329
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  • 16
    Electronic Resource
    Electronic Resource
    Torsion-rotation far-infrared spectrum of O-18 methanol (1994)
    Springer
    International journal of infrared and millimeter waves 15 (1994), S. 2021-2030 
    Details
    ISSN: 1572-9559
    Keywords: far-infrared ; FT spectroscopy ; methanol ; torsion ; CH3 18OH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High-resolution Fourier transform spectra have been recorded from 15–470 cm−1 for the far-infrared trosion-rotation band of O-18 methanol in the vibrational ground state. So far, 57 subbands have been assigned in the 15–220 cm−1 region for a wide range of rotational and torsional states, and their J-independent origins have been determined to an estimated accuracy of ±0.01 cm−1. The observed origins were found to deviate in many cases by several tenths of a cm−1 from the values calculated with the previous molecular parameters. Together with 4 known microwave origins, the new data have been fitted to a model torsion-rotation Hamiltonian in order to refine the set ofb-type molecular constants for the ground state. With the new parameter set, the experimental subband origins are reproduced with an rms error of ±0.02 cm−1, representing a substantial improvement over the earlier situation. The spectroscopic results have also been of great assistance with our assignments of optically-pumped FIR laser emission in CH3 18OH, in providing FIR data for checking the identification of the IR-pump/FIR-laser transition systems through combination loop relations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02096274
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  • 17
    Electronic Resource
    Electronic Resource
    Fourier Transform Spectrum and Term Values for the CO-Stretching Mode of CD3OH Methanol (2000)
    Springer
    International journal of infrared and millimeter waves 21 (2000), S. 1061-1083 
    Details
    ISSN: 1572-9559
    Keywords: infrared (IR) spectra ; methanol ; CD3OH ; torsion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Fourier transform infrared (FTIR) spectrum of the CO-stretching fundamental band of CD3OH has been recorded at a resolution of 0.002 cm-1. Assignments are reported for 35 subbands in the n = 0 ground torsional state, covering K = 0 to 9 for all torsional symmetries plus K = 10 A, and 12 assorted A and E subbands in the n = 1 first excited torsional state ranging from K = 0 up to K = 5. The subband wavenumbers have been fitted to J(J + 1) power-series energy expansions to obtain subband origins and a compact representation of the spectral observations. With the use of known ground-state energies, CO-stretch energy term values have been determined and tabulated. Least-squares fitting of the subband origins to a fourth-order Hamiltonian model for the CO-stretch mode is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026496304827
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  • 18
    Electronic Resource
    Electronic Resource
    Line positions and intensities in theν 2 band of D2O improvied pumped D2O laser frequencies (1985)
    Springer
    International journal of infrared and millimeter waves 6 (1985), S. 199-233 
    Details
    ISSN: 1572-9559
    Keywords: Fourier transform infrared spectroscopy ; Deuterated water vapor ; Laser frequencies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using high resolution Fourier transform spectra, thev 2 band of D2O has been analysed leading to an extensive and precise set of rotational energy levels of the (0 1 0) vibrational state. These levels are reproduced very satisfactorily with a Watson type Hamiltonian and precise rotational constants as well as the band centerv 2 = 1178.3789 ± 0.0005 cm-1 are determined. A total of 61 line intensities were measured, much attention being paid to a possible contamination of the D2O sample by HDO. A least squares fit of the intensity data has provided us with an expansion of the transition moment operator of thev 2 band from which the first derivative $$\left( {\frac{{\partial ^x \mu }}{{\partial q_2 }}} \right)_e $$ = 0.1690 ± 0.0030 D has been deduced. Finally the complete synthetic spectrum of this band has been computed. All these results have been used to derive improved frequencies for the known pumped and far-infrared laser lines of D2O and to predict new possible coincidences with the available CO2 laser lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01010358
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  • 19
    Electronic Resource
    Electronic Resource
    Torsional refilling transitions in tea-pumped CH3OH fir lasers with associated high-resolution fir spectra (1987)
    Springer
    International journal of infrared and millimeter waves 8 (1987), S. 1471-1482 
    Details
    ISSN: 1572-9559
    Keywords: Far-infrared (FIR) lasers ; methanol ; torsion ; FIR spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is proposed that a number of the high-frequency far-infrared (FIR) laser lines observed when CH3OH is optically pumped by high-power CO2 TEA lasers can be identified as refilling torsional transitions within the vibrational ground state. Assignments are presented for 8 such TEA-pump/FIR-laser refilling systems. To provide support for the assigned laser frequencies, high-resolution Fourier transform FIR spectra of CH3OH have been obtained and partially analyzed in the torsional transition region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01117773
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  • 20
    Electronic Resource
    Electronic Resource
    Applications of high resolution spectroscopy to the identification of far-infrared laser emission from optically pumped13CH3OH (1987)
    Springer
    International journal of infrared and millimeter waves 8 (1987), S. 1483-1502 
    Details
    ISSN: 1572-9559
    Keywords: Far-infrared (FIR) lasers ; methanol ; IR and FIR spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High-resolution infrared (IR) and far infrared (FIR) Fourier transform absorption spectra have been employed to investigate assignments of FIR laser lines reported from optically-pumped13CH3OH. The spectroscopic measurements are used in conjunction with the reported IR pump and FIR laser frequencies to form closed combination loops for several systems, serving to confirm the assignments and in some cases to improve the accuracy of the FIR laser frequencies. Frequency predictions from combination differences are also presented for a number of potential new FIR laser lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01117774
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