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1.
S.-X. Wang J. Schroderus I. Ozier N. Moazzen-AhmadiV.-M. Horneman V.V. IlyushynE.A. Alekseev A.A. KatrichS.F. Dyubko 《Journal of Molecular Spectroscopy》2002,214(1):69-79
An investigation of the torsion-rotation-vibration energies in the ν5 vibrational state in CH3CF3 has been carried out using infrared and mm-wave spectroscopy. The lowest frequency parallel fundamental band ν5 near 600 cm−1 has been measured at a resolution of 0.00125 cm−1 with Fourier transform spectroscopy for the two lowest torsional states v6=0 and 1. The cold band (v5=1, v6=0)←(v5=0, v6=0) showed no torsional splittings and looked much like a parallel band in a C3v molecule. The hot band (v5=1, v6=1)←(v5=0, v6=1) consisted of three distinct subbands, one for each torsional sublevel σ=0, +1, and −1. For the state (v5=1, v6=1), the torsional splitting was increased from ∼0.001 cm−1 to ∼0.022 cm−1 by torsion-mediated Fermi-type interaction primarily with the dark state (v5=0, v6=5). The effects of this coupling on the spectrum are striking in spite of the fact that the two interacting states are ∼100 cm−1 apart and differ by four units in v6. The large amplitude character of the state (v5=0, v6=5) is seen to be largely responsible for the unusual (k, σ) dependence of the energies in the state (v5=1, v6=1). The pure rotational spectrum in the state (v5=1, v6=0) has been measured between ∼50 and 370 GHz with Doppler-limited resolution; no σ-splitting was detected. The 3590 infrared and mm-wave frequencies measured here have been analyzed together with the 1494 measurements reported earlier by Wang et al. in an analysis of the vibrational ground state (2001, J. Mol. Spectrosc.205, 146-163). A good fit was obtained here by varying 36 parameters in a Hamiltonian which takes into account the interaction between the torsional stacks of levels for v5=0 and 1, as well as the (A1−A2) splittings measured earlier for v5=0. The explicit treatment of the interstack interactions is shown to lead to significant changes in the parameters (V0,3, V0,6) that characterize the torsional potential for v5=0. These changes have been explained quantitatively by examining the contact transformation that is implicitly applied when the interstack coupling is neglected. 相似文献
2.
Marcel Snels Giuseppe D'AmicoEl Bachir Mkadmi 《Journal of Molecular Spectroscopy》2002,216(2):191-196
The infrared spectra of isotopically pure CD235Cl2 have been recorded at a resolution of 0.0026 cm−1 (FWHM) in the range 600-1160 cm−1 with a Bruker IFS 120 HR Fourier transform interferometer. The absorption between 670 and 750 cm−1 is due to three fundamentals, ν3 (weak), ν7 (very weak), and ν9 (strong). A satisfactory analysis of the observed spectra has been obtained by including a c-Coriolis coupling between ν3 and ν9 and a b-Coriolis term between ν7 and ν9. Although no transitions could be observed for the very weak ν7 band, its band origin could be estimated from the Coriolis interaction with ν9. From the analysis of about 4200 assigned transitions of the ν3 and ν9 bands, excited state constants have been determined up to sextic terms. The Coriolis parameters obtained are compared to those calculated from a harmonic force field. 相似文献
3.
The Fourier transform infrared (FTIR) absorption spectrum of the ν12 fundamental band of ethylene-d4 (C2D4) was recorded in the 1017-1137 cm−1 region with an unapodized resolution of 0.0063 cm−1. Upper state (v12 = 1) rovibrational constants consisting of three rotational and five quartic constants were improved by assigning and fitting 2103 infrared transitions using Watson’s A-reduced Hamiltonian in the Ir representation. The band centre of the A-type ν12 band is found to be 1076.98480 ± 0.00002 cm−1. The present analysis covering a wider wavenumber range and higher J and Kc values yielded upper state constants including the band centre which are more accurate than previously reported. The rms deviation of the upper state fit is 0.00045 cm−1. Improved ground state rovibrational constants were also determined from the fit of 1247 ground state combination differences (GSCD) from the presently-assigned infrared transitions of the ν12 band of C2D4. The rms deviation of the GSCD fit is 0.00049 cm−1. In the rovibrational analysis, local frequency perturbations were not detected even at high J and Ka values. The calculated inertial defect Δ12 is 0.32551 ± 0.00001 μÅ2. The line intensities of the individual transitions in the ν12 band were measured and the band strength of 39.8 ± 2.0 cm−2 atm−1 was derived for the ν12 band of C2D4. 相似文献
4.
O.N. Ulenikov E.S. Bekhtereva O.L. Petrunina H. Bürger 《Journal of Molecular Spectroscopy》2003,219(1):13-29
The P-H stretching bands ν1/ν5 and 2ν1/ν1+ν5 were recorded using a Bruker 120 HR interferometer with a resolution of 0.0042 and 0.0088 cm−1, respectively, and analyzed. From the fits 33 and 50, respectively, vibrational, rotational, centrifugal distortion, and resonance interaction parameters were obtained. These reproduce 668 and 497 rovibrational energies of the pairs of states ν1/ν5 and 2ν1/ν1+ν5 with experimental accuracies, rms=0.00016 and , respectively. “Local mode” behavior of the PH2 fragment is established and discussed in detail. 相似文献
5.
The second overtone band 3ν1 of sulfur dioxide has been studied for the first time with high resolution rotation-vibration spectroscopy. About 3000 transitions involving about 900 upper state energy levels with have been assigned to the 3ν1 band. In the analysis, an effective Hamiltonian taking into account accidental interactions between the vibrational states (3 0 0), (2 2 0), and (0 4 1) was used. The Watson operator in A-reduction and Ir representation was used in the diagonal blocks of the Hamiltonian. As the result of analysis a set of parameters reproducing the initial experimental data with the rms = 0.00028 cm−1 was obtained. 相似文献
6.
J. Norooz Oliaee M. Dehghany A.R.W. McKellar 《Journal of Molecular Spectroscopy》2009,257(2):133-10422
Infrared spectra of OCS-C2H2 and OCS-C2D2 complexes in the region of the C-O stretching fundamental of OCS (∼2060 cm−1) are studied in a pulsed supersonic slit-jet expansion using a tunable diode laser. For each complex, two bands are observed and assigned to distinct near-parallel and the T-shaped isomers. Ground state parameters were previously determined from microwave studies, so analysis of the infrared spectra gives information on the vibrational shifts upon complex formation as well as rotational and centrifugal distortion parameters for the excited states. All four bands show a red shift with respect to the monomer band origin, with the T-shaped isomer having a much larger shift than the near-parallel isomer. Disappearance of the T-shaped isomer when argon is used as a carrier gas supports the notion that the near-parallel isomer is the lowest energy form of the complex. 相似文献
7.
Jeffrey BarberEngelene t.H. Chrysostom Tony MasielloJoseph W. Nibler Arthur MakiAlfons Weber Thomas A. BlakeRobert L. Sams 《Journal of Molecular Spectroscopy》2002,216(1):105-112
Further analysis of the high-resolution (0.0015 cm−1) infrared spectrum of 32S16O3 has led to the assignment of more than 3100 hot band transitions from the ν2 and ν4 levels to the states 2ν2 (l=0), ν2+ν4 (l=±1), and 2ν4 (l=0,±2). These levels are strongly coupled via Fermi resonance and indirect Coriolis interactions to the ν1 levels, which are IR-inaccessible from the ground state. The unraveling of these interactions has allowed the solution of the unusual and complicated structure of the ν1 CARS spectrum. This has been accomplished by locating over 400 hot-band transitions to levels that contain at least 10% ν1 character. The complex CARS spectrum results from a large number of avoided energy-level crossings between these states. Accurate rovibrational constants are deduced for all the mixed states for the first time, leading to deperturbed values of 1064.924(11), 0.000 840 93(64), and 0.000 418 19(58) cm−1 for ν1, α1B, and α1C, respectively. The uncertainties in the last digits are shown in parentheses and represent two standard deviations. In addition, new values for some of the anharmonicity constants have been obtained. Highly accurate values for the equilibrium rotational constants Be and Ce are deduced, yielding independent, nearly identical values for the SO re bond length of 141.734 03(13) and 141.732 54(18) pm, respectively. 相似文献
8.
Kensuke Harada Makoto Hatanaka Akira Inayoshi Keiichi Tanaka Takehiko Tanaka 《Journal of Molecular Spectroscopy》1984,108(2):249-263
The LMDR (laser-microwave double resonance) spectroscopy with an intense electric field was applied to the ν5 (CF3 degenerate stretch) fundamental band of CDF3. The dipole moments and polarizability anisotropies in the ground and ν5 vibrational states were determined as follows.
Ground | ||||||
μ (D) | 1.653 511 (29) | 1.658 514 (23) | ||||
α (Å3) | ?0.77 (32) | ?0.58 (48) |
CD379Br | CD381Br | |||||
991.396 82 (18) | 991.388 46 (17) | cm?1 | ||||
1055.469 00 (12) | 1055.466 32 (12) | cm?1 | ||||
1.830 42 (52) | 1.829 84 (47) | D | ||||
1.829 93 (48) | 1.829 57 (46) | D | ||||
1.832 23 (60) | 1.831 19 (56) | D |
35ClO2 | 37ClO2 | |||||
945.592 357(60) | 939.602 909(66) | cm?1 | ||||
μ′ | 1.788 39(13) | 1.788 46(15) | D | |||
μ″ | 1.791 95(10) | 1.792 10(13) | D | |||
δμ | ?0.003 56(18) | ?0.003 64(26) | D |
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