共查询到20条相似文献,搜索用时 15 毫秒
1.
The infrared spectra of CH2=CHF have been investigated in the ν5 and ν6 band regions between 1280 and 1400?cm?1, at a resolution of about 0.002?cm?1, using a tunable diode laser spectrometer. These vibrations of symmetry species A′ give rise to a/b-hybrid bands with different contributions from both the components. Spectral analysis resulted in the identification of 1565 (J≤46, K a ≤11) and 1651 (J≤48, K a ≤15) transitions of the ν5 and ν6 fundamentals, respectively. Both bands are perturbed by the nearby states ν8?+?ν9 and ν9?+?ν11 through different Coriolis resonances and an anharmonic interaction. Using Watson's A-reduction Hamiltonian in the Ir representation and perturbation operators almost all the transitions have been fitted simultaneously to a model including six resonances within the tetrad ν5/ν6/ν8?+?ν9/ν9?+?ν11. A set of spectroscopic constants for the ν5 and ν6 bands, as well as parameters for the dark states ν8?+?ν9 and ν9?+?ν11 and coupling constants, have been determined. From spectral simulations the dipole moment ratio |Δμ a /Δμ b | was estimated to be 0.6?±?0.1 and 2.0±0.3 for the ν5 and ν6 bands, respectively. 相似文献
2.
Fourier transform spectra of ethylene (C2H4) have been recorded in the 1800–2350?cm?1 (4.3–5.6?µm) spectral region using a Bruker IFS125HR spectrometer at a resolution of 0.004?cm?1 leading to the observation of six vibrational bands, ν 7?+?ν 8, ν 4?+?ν 8, ν 6?+?ν 10, ν 6?+?ν 7, ν 4?+?ν 6 and ν 3?+?ν 10. The corresponding upper state ro-vibrational levels were fit using a Hamiltonian matrix accounting for numerous interactions. A satisfactory fit could be obtained using a polyad of nine interacting states {81101,?7181,?4181,?81121,?61101,?6171,?4161,?31101,?3171} of which three (81101, 81121 and 3171) are unobserved dark states. As a result a much more accurate and extended set of Hamiltonian constants were obtained than previously derived. The following band centers were determined: ν 0(ν 7?+?ν 8)?=?1888.9783(20)?cm?1, ν 0(ν 4?+?ν 8)?=?1958.2850(20)?cm?1, ν 0(ν 6?+?ν 10)?=?2047.7589(20)?cm?1, ν 0(ν 6?+?ν 7)?=?2178.011(60)?cm?1, ν 0(ν 4?+?ν 6)?=?2252.8026(24)?cm?1 and ν 0(ν 3?+?ν 10)?=?2171.2397(20)?cm?1. Finally, a synthetic spectrum that could be useful for ethylene detection in planetary atmospheres was generated. 相似文献
3.
G. WEIRAUCH M. I. EL IDRISSI J. VANDER AUWERA M. HERMAN A. CAMPARGUE 《Molecular physics》2013,111(11):969-980
The absorption spectrum of dideuteroacetylene has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10 200–12 500cm?1 spectral region. Among 25 absorption bands of 12C2D2 rotationally analysed in this spectral region, 17 are newly observed. They include one IIu-Σ+ g and thirteen Σ+ u-Σ+ g bands starting from the vibrational ground state and eleven hot bands from the V 4 = 1 and V 5 = 1 lower states. The rotational structure of two excited levels is affected by a strongly J-dependent interaction with a perturber which induces intensity transfer to extra lines. The coupling is identified as a I-resonance interaction with δu dark states and the vibrational assignment of the perturbers is discussed. Two Σ-Σ bands of the 12C13 CD2 species, present in natural abundance in the sample, could also be identified and rotationally analysed. Most of the corresponding excited vibrational levels of 12C2D2 were unambiguously assigned using the polyad model [Herman, M., el idrissi, M. I., Pisarchik, A., Campargue, A., Gaillot, A.-C., Biennier, L., di lonardo, G. and Fusina, L., 1998, J. chem. Phys., 108, 1377] which allows vibrational energies and B V rotational constants to be predicted. In particular the previously highlighted 1/244 anharmonic resonance is confirmed by energy and intensity features in several {(V 1, V 2, V 3, V 4 = 0, V 5 = 0),(V 1 ?1, V 2 + 1, V 3 V 4 = 2, V 5 = 0)} dyads. Significant deviations between predicted and experimental energy levels are observed for a few levels and discussed. 相似文献
4.
The infrared spectrum of 12C2HD has been observed between 1800 and 4700?cm?1 by Fourier transform spectroscopy. The ν1, ν2 and ν3 absorption bands and the associated hot and combination bands involving the bending modes up to υt?=?υ4?+?υ5?=?2 have been investigated. Altogether, 60 vibrational bands were analysed, leading to the spectroscopic characterization of 31 vibrationally excited states. Several perturbations have been observed, but the transitions involving the perturbing states have not been detected. As a consequence, an appropriate treatment of the vibrational or ro-vibrational interactions has not been possible. A tentative assignment of the perturbing states has been proposed. Eventually, global fits for each fundamental vibration and its associated cold and hot bands have been performed. 相似文献
5.
6.
《Journal of Molecular Spectroscopy》1987,124(2):379-392
The v = 1 ← 0 vibration-rotation absorption bands of 32S16O, 34S16O, and 32S18O in the ground electronic state, X3Σ−, and the v = 1 ← 0 vibration-rotation band of 32S16O in the first excited electronic state, a1Δ, were measured at 0.004 cm−1 unapodized resolution with a high-resolution Fourier transform spectrometer coupled to a long path absorption cell. The v = 2 ← 0 vibration-rotation band of 32S16O in the X3Σ− state was also observed. Line positions for P- and R-branch transitions up to N = 44 for 32S16O have been measured and analyzed yielding improved molecular parameters. The present measurements are compared with previous infrared and microwave measurements. 相似文献
7.
《Journal of Molecular Spectroscopy》1986,116(2):286-314
The excitation spectrum of BaO in the region above 32 000 cm−1 was investigated with a frequency-doubled pulsed dye laser. We have observed fully developed rotational structures of the C1Σ+-X1Σ+ transition. The analysis of the vibrational states v′ = 0 through 7 leads to a large number of perturbations. This spectroscopic information in combination with the observation and rotational analysis of transitions to several new electronic states allows a systematic summary, which gives more than eight electronic states in the investigated region. Besides the known states B, C, D and c, we find four new bound states, designated by E, F, G, and H. For all states molecular constants are given. The discussion of possible molecular electron configurations leads to classifications of the molecular electronic states. Our results on the vibrational levels v′ = 0 to 3 are in reasonable agreement to the optical-optical double resonance work of R. A. Gottscho, P. S. Weiss, and R. W. Field [J. Mol. Spectrosc. 82, 283–309 (1980)], but show several new details. 相似文献
8.
9.
S. N. Mikhailenko V. I. Serdyukov L. N. Sinitsa S. S. Vasilchenko 《Optics and Spectroscopy》2013,115(6):814-822
The spectrum of H2 18O in the range 15000–15700 cm?1 has been recorded for the first time on a Fourier-transform spectrometer using a high-brightness light-emitting diode as a radiation source. The measurements have been conducted at room temperature with a resolution of 0.05 cm?1. A threshold sensitivity in absorption of 2 × 10?7 cm?1 has been achieved due to both the use of a light-emitting diode and optimization of the multipass cell with a base length of 60 cm, which ensured a 19.2-m length of the absorbing layer. A high signal-to-noise ratio (S/N = 2000–10000) made it possible to record about 670 water-vapor lines with intensities of 1.0 × 10?26–2.2 × 10–24 cm/mol at 296 K. The energies of 265 vibrational-rotational levels of the H2 18O molecule are determined and attributed to seven vibrational states, namely, (033), (113), (212), (231), (311), (330), and (410). 相似文献
10.
A. PIETROPOLLI CHARMET P. STOPPA R. VISINONI S. GIORGIANNI G. NIVELLINI 《Molecular physics》2013,111(22):3529-3534
The gas-phase infrared spectra of natural CH2 = CClF have been measured in the v 6 and 2v 12 band regions (930–1050 cm?1) by high-resolution Fourier transform spectroscopy at room temperature. 1-Chloro-1-fluoroethylene is a planar asymmetric rotor (κ = ?0.54) belonging to the symmetry point group Cs and the vibrations investigated of symmetry species A′ give rise to a/b-hybrid bands with contributions of comparable intensity from both the components. The rovibrational analysis of the fine structure led to the identification of 1894 (J ? 73, Ka ? 20) and 718 (J ? 53, Ka ? 8) transitions for the v 6 and 2v 12 bands of the 35Cl isotopic species, respectively. Using the Watson's A-reduction Hamiltonian in the Ir representation a set of accurate spectroscopic parameters for both the excited states u 6 = 1 and u12 = 2 of 35Cl has been obtained for the first time. Transitions of 37Cl isotopomer could also be assigned in the Q branch region of the 2v 12 overtone; the determined band origin shift of 0.782 cm?1 towards the lower wavenumbers led to describing the v 12 fundamental as a vibration mainly involving the CFCl bending motion. 相似文献
11.
《Molecular physics》2012,110(21-22):2621-2632
The vibration–rotation spectra of 13C substituted acetylene, 13C2H2, have been recorded in the region between 60 and 2600?cm?1 at an effective resolution ranging from 0.001 to 0.006?cm?1. Three different instruments were used to collect the experimental data in the extended spectral interval investigated. In total 9529 rotation vibration transitions have been assigned to 101 bands involving the bending states up to v tot?=?v 4?+?v 5?=?4, allowing the characterization of the ground state and of 33 vibrationally excited states. All the bands involving states up to v tot?=?3 have been analyzed simultaneously by adopting a model Hamiltonian which takes into account the vibration and rotation l-type resonances. The derived spectroscopic parameters reproduce the transition wavenumbers with a RMS value of the order of the experimental uncertainty. Using the same model, larger discrepancies between observed and calculated values have been obtained for transitions involving states with v tot?=?4. These could be satisfactorily reproduced only by adopting a set of effective constants for each vibrational manifold, in addition to the previously determined parameters, which were constrained in the analysis. 相似文献
12.
13.
O.M. Lyulin E.V. Karlovets D. Jacquemart Y. Lu A.W. Liu V.I. Perevalov 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(17):2167-2181
The assignment of the high resolution Fourier transform spectra of carbon dioxide enriched in 17O and 18O which were recorded in LADIR (Paris, France) with the Bruker IFS 125-HR between 1800 and 9000 cm?1 and in USTC (Hefei, China) with the Bruker IFS 120-HR between 1700 and 9000 cm?1 was performed. In total 239 bands of 12 isotopologues: 16O12C16O, 16O12C18O, 16O13C16O, 16O13C18O, 18O12C18O, 18O13C18O, 16O12C17O, 17O12C17O, 17O12C18O, 16O13C17O, 17O13C17O and 17O13C18O were observed. Among them, 99 bands were observed for the first time. The majority of new observed bands belong to 17OCO isotopologues. The positions of 23,003 lines were determined with the experimental uncertainty on the level of 0.001 cm?1. The spectroscopic constants were fitted to the observed line positions for all observed bands. 相似文献
14.
ABSTRACTWe have recorded the a4Σ? 3/2 ? X1 2Π3/2 (0,0), (1,0), and (2,0) bands of gaseous gold monosulphide (AuS) at sub-Doppler resolution in the near-infrared region. The molecules were made in a hollow cathode discharge source by the reaction of sputtered gold with carbonyl sulphide. The high resolution of the laser excitation spectrum enabled the determination of molecular constants describing the rotational and 197Au hyperfine structure in both states, as well as the spin–rotation interaction in the a4Σ? 3/2 state. The natures of the two electronic states are discussed in the context of the observed hyperfine structure. 相似文献
15.
G. Di Lonardo L. Fusina A. Baldan R. Z. Martínez D. Bermejo 《Molecular physics》2013,111(21):2533-2542
Infrared and Raman spectra of dideuterated acetylene containing one 13C atom, 13C12CD2, have been recorded and analysed to obtain detailed information on the fundamental ν 2 band and associated combination and hot bands. Infrared spectra were recorded at 4?×?10?3?cm?1 resolution in the region 1150?2900?cm?1, which contains combination and hot bands from the ground and the bending v 4?=?1 and v 5?=?1 states. The Q-branches of the ν 2 fundamental and associated hot bands (ν 2?+?ν 4???ν 4, ν 2?+?ν 5???ν 5, ν 2?+?2ν 4???2ν 4, ν 2?+?2ν 5???2ν 5 and ν 2?+?ν 4?+?ν 5???(ν 4?+?ν 5)) were recorded using inverse Raman spectroscopy, with an instrumental resolution of about 3?×?10?3?cm?1. In addition, the observation of the 2ν 2???ν 2 Raman band was carried out populating the v 2?=?1 state by stimulated Raman pumping. In total, 11 Raman and 9 infrared bands were analysed, involving all the l-vibrational components of the excited stretching?bending manifolds up to v t ?=?v 4?+?v 5?=?2. A simultaneous analysis of all infrared and Raman assigned transitions has been performed on the basis of a theoretical model which takes into account the rotation and vibration l-type resonances within each vibrational manifold and the Darling?Dennison anharmonic resonance between the ν 2?+?2ν 4 and ν 2?+?2ν 5 states. The parameters obtained reproduce the assigned transition wavenumbers with a standard deviation of the same order of magnitude as the experimental uncertainty. 相似文献
16.
The absorption spectrum of 12C2H2 has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10600–11 500 cm?1 spectral region, where no absorption bands were previously reported. Fifteen bands starting from the vibrational ground state are observed and rotationally analysed. All corresponding excited vibrational levels were assigned using the polyad model, the so-called cluster model (El Idrissi, M.I., Liévin, J., Campargue, A., and Herman, M., 1999, J. chem. Phys., 110, 2074) which allows vibrational energies, rotational Bv constants and, to some respect, relative band intensities to be predicted. Additional data and constants are also provided in the range 7600–9200cm?1, whenever improving the literature results, from spectra recorded previously at ULB using Fourier transform spectroscopy. The assignment procedure in the range recorded by ICLAS is detailed, leading to a deeper understanding of vibration-rotation and intensity features of the absorption bands within the frame of the cluster model. 相似文献
17.
N. Hunt S.C. Foster J.W.C. Johns A.R.W. McKellar 《Journal of Molecular Spectroscopy》1985,111(1):42-53
The spectrum of OCS with natural isotopic abundances has been measured in the 1975- to 2140-cm?1 region with near-Doppler-limited resolution using a Fourier transform spectrometer. Sixteen bands have been analyzed, including the following five bands for the first time at high resolution:
16O13C32S | 1000-0000 | 2009.228 cm?1 |
16O13C32S | 1110-0110 | 2002.427 cm?1 |
18O12C32S | 1000-0000 | 2026.147 cm?1 |
16O12C32S | 0400-0000 | 2104.828 cm?1 |
16O12C32S | 0510-0110 | 2115.169 cm?1 |