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1.
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 (A1A2) 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.
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.
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.
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.
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), ν24 (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.
The ν2 (CD3 symmetrical deformation) and ν5 (CD3 degenerate deformation) fundamental bands of CD3Br were studied by 9.4- and 10.4-μm CO2 laser Stark spectroscopy. Stark resonances originating from 28 and 53 rovibrational transitions of the ν2 and ν5 bands, respectively, were assigned for each of the isotopic species, CD379Br and CD381Br. These two bands were simultaneously analyzed with explicit inclusion of the ν2-ν5 Coriolis interaction, yielding precise molecular constants in the ν2 and ν5 excited states as well as the Coriolis coupling constant. The molecular constants obtained are consistent between the two isotopic species and are in good agreement with the results of high-resolution infrared studies. The band origins and dipole moments are
  相似文献   

9.
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.
CD379BrCD381Br
ν2991.396 82 (18)991.388 46 (17)cm?1
ν51055.469 00 (12)1055.466 32 (12)cm?1
μ01.830 42 (52)1.829 84 (47)D
μ21.829 93 (48)1.829 57 (46)D
μ51.832 23 (60)1.831 19 (56)D
  相似文献   

10.
The high resolution infrared spectrum of the mono-isotopic species F35Cl16O3 has been studied in the region of the 2ν4 overtone, from 2560 to 2680 cm−1. The perpendicular component is strong and clearly observed while the parallel component is very weak and almost completely hidden by the perpendicular one. Their origins differ by 12.6 cm−1, the being located at higher wavenumbers. The band is perturbed by the anharmonic interaction between the v4 = 2, l4 = ?2 and v2 = v4 = v5 = 1, l4 = l5 = ±1 excited states, both of E symmetry. In total 3157 transitions have been assigned, 83% of these to , 12% to , and 5% to . The three bands have been analyzed simultaneously, taking into account the Fermi resonance effective between the excited states of E symmetry. The ro-vibration parameters of the excited states have been obtained, including the deperturbed band origins of and , at 2628.5890(4) and 2619.3342(5) cm−1, respectively. The W245 anharmonic constant is equal to 4.0161(4) cm−1. The x44+g44 and x24+x45+g45 anharmonicity constants have been derived from the obtained band origins and those of ν4 and ν2 + ν5.  相似文献   

11.
Nitric acid which is an important NOx atmospheric reservoir molecule exhibits a strong absorption in the spectral region. Since this region, which corresponds to an atmospheric window, is one of the most commonly used for the retrieval of HNO3 in the atmosphere it is essential to have the best possible corresponding spectral parameters. Updates of these spectral line parameters were recently performed in the last versions of the atmospheric databases. They concern the line positions and intensities not only of the two interfering cold bands ν5 and 2ν9 but also of the ν5+ν9ν9 hot band. This hot band exhibits indeed a sharp and strong Q branch at which is clearly observable in atmospheric spectra and is used for the retrievals. However, in spite of these recent updates, it proved that the spectral parameters of the hot band are not accurate enough to reproduce accurately the observed atmospheric HNO3 absorption in ATMOS spectra. The present paper is dedicated to a more accurate analysis of this hot band using new laboratory high-resolution (0.002-) Fourier transform spectra. As a consequence, new and more precise line positions and line intensities (about 35% weaker than in HITRAN2K) were derived leading to a significant improvement in the simulation of atmospheric spectra.  相似文献   

12.
The ν1 fundamental band of the ClO2 radical has been studied by means of the 10.6-μm CO2 and N2O laser Stark spectroscopy. More than 250 and 150 Stark resonances were assigned for the 35ClO2 and 37ClO2 species, respectively, and were analyzed together with the recent microwave and laser-microwave double resonance results to give molecular constants including spin-rotation interaction constants. The ν1 band origins and electric dipole moments both in the ground and ν1 states were determined accurately
Groundν5
μ (D)1.653 511 (29)1.658 514 (23)
α (Å3)?0.77 (32)?0.58 (48)
  相似文献   

13.
潘峰 《中国物理 C》1991,15(2):178-186
本文讨论了SO5 SU2 SU2 U1 U1及SO5 U1 U1的VCS表示.计算了SO5 U2 U2的约化矩阵元,并利用K矩阵技术确定了SO5权的多重度.  相似文献   

14.
The infrared spectra of the 2ν1, 2ν2 and 2ν3 overtones of perchloryl fluoride, FClO3, have been recorded at high resolution using monoisotopic pure samples. Four symmetric top species have been investigated: F35Cl16O3, F37Cl16O3, F35Cl18O3 and F37Cl18O3. The vi = 2, i = 1, 2, 3 vibrationally excited states are totally symmetric, so these overtones correspond to parallel bands of medium/weak intensity, centered from 2010 to 2120 cm−1 (2ν1), from 1390 to 1430 cm−1 (2ν2) and from 1070 to 1100 cm−1 (2ν3). Most of the bands are unperturbed and their analysis was straightforward. The band origins, the rotational and centrifugal molecular constants in the v1 = 2, v2 = 2 and v3 = 2 states have been determined, with standard deviations of the fits from 0.00024 to 0.00067 cm−1. The 2ν1 overtones of F35Cl16O3 and F37Cl16O3 are perturbed by an A1/E Coriolis resonance between the v1 = 2 state and one E component of the v4 = 1, v6 = 2 manifold. The 2ν2 of F37Cl18O3 is perturbed by the same kind of interaction involving the v1 = v6 = 1 (E) state, at about 1396 cm−1. In these bands the resonance is localized on rotational levels with specific J and K values. As a consequence, a few transitions of the perpendicular bands involving the interacting levels could be identified in the spectra. A simultaneous fit of the transitions assigned to the dyads has been performed and the parameters of the excited states have been determined, including the high order Coriolis interaction coefficient . The anharmonic constants x11, x22, x33 of all the studied isotopologues of FClO3, x46 of F35Cl16O3, x46 + g46 of F37Cl16O3 and x16 of F37Cl18O3, have been derived.  相似文献   

15.
IR spectra of the solution of SF6 molecules in liquid NF3 at 84 K have been recorded. In a solvent transmission window of 1500–1750 cm−1, two wide absorption bands with pronounced peaks in the high-frequency part are observed. The profile of these bands is explained by the influence of the resonance dipole-dipole (RDD) interaction of the states of the simultaneous transition ν1(SF6) + ν3(NF3) and ν2(SF6) + ν3(NF3) with the states (ν1 + ν3) and (ν2 + ν3) of the SF6 molecules, respectively. The use of three isotopic modifications 32SF6, 33SF6, and 34SF6 has allowed us to vary the resonance detuning and thus to change the strength of the RDD interaction. With the liquid near the melting point being represented as a close-packed cubic crystal, the profile was calculated and its spectral characteristics were determined. The frequencies of the main peaks coincide with the experimental values accurate to the error.  相似文献   

16.
TiO2, RuO2, and IrO2 transition metal oxides have many applications in the field of applied electrochemistry. In this work, the mixed solid solutions of TiO2–RuO2–IrO2 coatings have been electrodeposited from aqueous–unaqueous baths.  相似文献   

17.
xCeO2–30Bi2O3–(70−x) B2O3 glasses are synthesized by using the melt quench technique. A number of studies such as XRD, density, molar volume, optical band gap, refractive index and FTIR spectroscopy are employed to characterize the glasses. The band gap decreases from 2.15 to 1.61 eV, refractive index increases from 2.67 to 2.93 and density increases from 4.151 to 4.633 g/cm3. The decrease in band gap with CeO2 doping approaches the semiconductor behavior. FTIR spectroscopy reveals that incorporation of CeO2 into glass network helps to convert the structural units of [BO3] into [BO4] and results in Bi–O bond vibration of [BiO6].  相似文献   

18.
The 71 and 91 vibrational states of deuterated species of formic acid molecule DCOOH have been recorded by a FTIR spectrometer in the region 450- at a resolution of and a millimeter wave spectrometer. In the analysis microwave transitions from literature were used in addition to 14 835 assigned IR and 114 millimeter wave lines in the 71 and 91 vibrational states. The analysis resulted in band origins, rotational, centrifugal distortion, and eight interaction parameters of the Coriolis coupled 71 and 91 vibrational states. RMS deviation of the fit was for the IR data and the maximum values of J and Ka quantum numbers in the fit were 64, 28 and 64, 30 for 71 and 91 states, respectively.  相似文献   

19.
20.
The spectrum of the ν7 band of cis-ethylene-d2 (cis-C2H2D2) has been recorded with an unapodized resolution of 0.0063 cm−1 in the 740-950 cm−1 region using a Bruker IFS 125 HR Fourier transform infrared spectrometer. By fitting 2186 infrared transitions of ν7 with a standard deviation of 0.00060 cm−1 using a Watson’s A-reduced Hamiltonian in the Ir representation, accurate rovibrational constants for ν7 = 1 state have been derived. The band center of ν7 has been found to be 842.20957 ± 0.00004 cm−1. In a simultaneous fit of 1331 infrared ground state combination differences from the present ν7 transitions, together with 22 microwave frequencies, ground state constants have been improved. The rms deviation of the ground state fit was 0.00027 cm−1.  相似文献   

35ClO237ClO2
ν0945.592 357(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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