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1.
The second CH stretching overtone of cyanoacetylene, HC3N, near 9700 cm−1 has been recorded by Fourier Transform Spectroscopy (FTS) and by Intracavity Laser Absorption Spectroscopy (ICLAS) with a Vertical External Cavity Surface Emitting Laser (VECSEL). In total thirteen bands have been identified in the highly congested spectra and rotationally assigned. Their rovibrational spectroscopic parameters have been obtained from a fit of the line centers. 相似文献
2.
A high-resolution (up to 0.0018 cm−1 unapodized) room temperature mid-infrared (650 to 750 cm−1, 13.3 to 15.4 μm) absorption measurement of the ν3 vibrational band of trifluoromethane (fluoroform, CHF3, HFC-23) vapor was made with a Fourier transform spectrometer. A rovibrational analysis of over 1400 infrared transitions of the ν3 band has yielded rotational constants, including sextic centrifugal distortion constants. The results are compared with two previous analyses of microwave and infrared spectra. The line positions of the lower J parts of the ν3+ν6−ν6 and 2ν3−ν3 hot bands have been identified and constants obtained for the 2ν3 state. The central Q branch and a few unblended transitions of the ν3 band of 13CF3H have been identified and the band origin has been determined. The relative intensities of the ν3 band together with the 2ν3−ν3 hot band and ν3 band of 13CF3H have been calculated using the constants derived from this work. 相似文献
3.
N. Boulaftali N. Ben Sari-Zizi H. Najib G. GranerH. Bürger E.B. MkadmiP. Pracna 《Journal of Molecular Spectroscopy》2002,214(1):35-51
The ν1 (A1, 1578.31 cm−1)/ν4(E, 1615.17 cm−1) Si-D stretching dyad of D3SiF has been studied by FTIR spectroscopy with a resolution of 2.4×10−3 cm−1. Only weak interactions of Coriolis (ΔK=±1, Δ?=±1) and α resonance (ΔK=±2, Δ?=?1) type between ν1 and ν4, and of ? (2,−4) type within ν4, were revealed. However, the v1=1 and v4=1 levels were found to be severely perturbed by the v3=v5=1 (E, 1590.37 cm−1) and v2=v3=1 (A1, 1604.25 cm−1) states. These perturbations are observable only near level crossings involving strong Coriolis and α interactions. The energy structure within these perturbers is severely complicated by strong Coriolis and α resonances and by ? (2, 2), ? (2,−1), and ? (2,−4) interactions as already revealed by the ν2(A1, 710.16 cm−1) and ν5 (E, 701.72 cm−1) fundamentals. Interactions of the perturbing states with the ν1/ν4 dyad are particularly evident in local crossings. In total, 12 transitions belonging to the dark states and 68 perturbation-allowed transitions within the ν1/ν4 dyad have been detected among the more than 5000 transitions that have been assigned for the ν1/ν4 dyad, with Jmax and Kmax of 50 and 30, respectively. Altogether about 85% of the assigned transitions were fitted with a standard deviation of 0.221×10−3 cm−1, leading to 61 parameters of the interacting polyad. 相似文献
4.
The temperature variations in collision-induced absorption (CIA) spectra of carbon dioxide in the region of the Fermi doublet are examined. New FTIR CIA spectra are recorded in the temperature range T=206-296 K. The spectra were subject to decomposition in order to separate true dimer contributions to the CIA profile from the base absorption caused by unbound pairs. The use of statistical physics theory allowed for quite nice reproduction of the observed temperature variations of the normalized dimer intensity. 相似文献
5.
The ν1 (A1, 1583.22 cm−1) and ν4 (E, 1615.33 cm−1) Si-D stretching bands of monoisotopic D3Si35Cl have been studied by FTIR spectroscopy with a resolution of 3.3×10−3 cm−1. We have assigned 2341 rovibrational lines for ν1 (Jmax=70, Kmax=19) and 6207 for ν4 (Jmax=75, Kmax=27). Both (ΔK=±1, Δ?=±1) and (ΔK=±2, Δ?=?1) interactions connect the v1=1 and v4=1 levels, the latter exerting moreover a weak ?(2, 2) interaction. These interactions were taken into account in a nonlinear least-squares fit, refining 29 free parameters with a standard deviation of 0.257×10−3 cm−1 over 6722 nonzero-weighted data. Blended lines and about 250 of the 330 lines belonging to the K=11 subband of ν1 and the KΔK=−6 subband of ν4 were zero-weighted because they are locally perturbed respectively by the neighboring upper states of the 2ν3+ν6 (E, 1561.95 cm−1) and 3ν3 (A1, 1604.81 cm−1) bands. Equivalent fits were obtained for altogether three different models obeying constraints according to the theory of unitary equivalent reductions of the rovibrational Hamiltonian. By means of a band contour simulation both the transition moment ratio |M1:M4|=0.67 and a positive sign of the Coriolis intensity perturbation were determined. 相似文献
6.
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
7.
D Hurtmans G DufourW Bell A HenryA Valentin C Camy-Peyret 《Journal of Molecular Spectroscopy》2002,215(1):128-133
We have determined the spectroscopic parameters that are necessary to describe accurately the R(0) line profile of the CH4 2ν3 band from about 1 Torr to a few hundred Torr of pure CH4. The intensities determined at each pressure are in overall agreement to better than 0.7%. The R(3) manifold of the same band has also been investigated. Relative positions and absolute intensities of the three transitions composing the triplet have been determined. The intensity distribution inside the triplet is in fair agreement with recent theoretical predictions. 相似文献
8.
O.N Ulenikov E.S Bekhtereva V.A Kozinskaia Jing-Jing ZhengSheng-Gui He Shui-Ming HuQing-Shi Zhu C LeroyL Pluchart 《Journal of Molecular Spectroscopy》2002,215(2):295-308
The high-resolution (0.005 cm−1) Fourier transform infrared spectrum of PH3 is recorded and analyzed in the region of the fundamental stretching bands, ν1 and ν3. The ν2+ν4 and 2ν4 bands are taken into account also. Experimental transitions are assigned to the ν1, ν3, ν2+ν4, and 2ν4 bands with the maximum value of quantum number J equal to 15, 15, 13, and 15, respectively. a1-a2 splittings are observed and described up to the value of quantum number K equal to 10. The analysis of a1/a2 splittings is fulfilled with a Hamiltonian model which takes into account numerous resonance interactions among all the upper vibrational states. 相似文献
9.
The high-resolution infrared spectrum of allene has been observed in the 280-380 cm−1 region at a nominal resolution of 0.00125 cm−1 using the IR beamline at the MAX-I electron storage ring in Lund. The spectrum shows the bending fundamental of the ν11 band from which spectroscopic constants for the ν11 level have been obtained. The accompanying hot band component 2ν112-ν111 has also been assigned and analyzed. 相似文献
10.
The diode laser spectrum of the ν1 fundamental band of the short-lived molecule PNO has been detected with 59 R- and P-branch lines accurately measured. The lines were unambiguously assigned using the rotational and distortion constants for the ground and (100) vibrational levels found previously by microwave spectroscopy. The band origin was determined to be 860.301 228(31) cm−1 from a one parameter fit. The gas phase band origin is red-shifted by approximately 4 cm−1 from the matrix value. 相似文献
11.
R. Milloud S.A. Tashkun 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(3):553-557
The absorption spectrum of nitrous oxide (N2O) has been recorded by Intracavity Laser Absorption Spectroscopy between 12,760 and 12,900 cm−1. The rotational analysis led to an improved determination of rovibrational parameters of the 6ν3 and 6ν3+ν2-ν2 bands of 14N216O. The high J rotational levels of the (0 0 06) and (0 1 16) upper states were found perturbed by an anharmonic interaction. Line intensity values of the 6ν3 band are provided and the main effective dipole moment parameter has been determined. 相似文献
12.
S.N. Mikhailenko VL.G. TyuterevV.I. Starikov K.K. AlbertB.P. Winnewisser M. Winnewisser G. MellauC. Camy-Peyret R. LanquetinJ.-M. Flaud J.W. Brault 《Journal of Molecular Spectroscopy》2002,213(2):91-121
Water vapor infrared spectra have been recorded at room temperature in the range 4200-6250 cm−1 at resolutions (FWHM) between 0.0053 and 0.0080 cm−1. The use of a White-type multireflection cell made large pressure × pathlength products possible up to 31.27 mbar×288.5 m. The high signal-to-noise ratio allowed us to observe lines with intensities as small as 10−26 cm−1/molecule cm−2 at T=296 K. Among about 5100 recorded water lines, about half of which are reported for the first time, 2351 lines have been assigned to the second triad of H216O (bands ν1+ν2, ν2+ν3, and 3ν2). This has allowed the determination of line positions and corresponding upper rovibrational states with considerably improved accuracy. The assignments of certain highly excited states have been confirmed by the analysis of flame spectra and hot emission spectra. New values of effective Hamiltonian parameters for the upper states {(110), (030), (011)} have been determined. The generating function model was used in the data reduction to account for the anomalously strong centrifugal distortion of the rovibrational levels and resonance interactions. The RMS standard deviation of the least-squares fit of the assigned H2O data was 5×10−3 cm−1 for line positions and 7×10−3 cm−1 for energy levels up to Jmax=20 and Ka(max)=13. Particular attention was paid to water lines in the transparency window 4200-5000 cm−1, in which existing databases are not sufficient. In this region, 1395 lines of four isotopic species of water have been recorded and over 900 accurate line positions of nine bands of H216O (ν1, ν3, 2ν2, ν1+ν2, ν2+ν3, 3ν2, 4ν2−ν2, 2ν2+ν3−ν2, ν1+2ν2−ν2) are reported in this range. A comparison of laboratory spectra with long path atmospheric spectra (20 km slant path in the mountains) in this region shows that many lines missing from available spectroscopic compilations (or considerably shifted compared to observations) are important for a proper interpretation of atmospheric observations. A comparison of the observed data with the best available predictions from the molecular electronic potential energy surface is discussed. 相似文献
13.
The (0,0) vibronic band of NiCl system G with a bandhead near 12 961 cm−1 was recorded at high resolution in absorption using intracavity laser spectroscopy (ILS). For the ILS absorption spectra, the NiCl molecules were produced in a nickel hollow cathode, operated with a small amount of CCl4, and line positions were referenced to iodine spectra. Fourier transform (FT) emission spectroscopy was used to record an extensive region of the spectrum used in a vibronic analysis of system G. For the FT spectra, excited NiCl molecules were produced in a high-temperature King-type carbon tube furnace. We show that this transition is the (0,0) vibronic band associated with a newly identified 2Π3/2 excited state and the X2Π3/2 ground state. The molecular constants for the new 2Π3/2 electronic state are derived from the rotational analysis. Improved vibronic constants for the band are obtained from analysis of the FT spectra. 相似文献
14.
O.N Ulenikov O.L Petrunina E.S Bekhtereva E.A Sinitsin H BürgerW Jerzembeck 《Journal of Molecular Spectroscopy》2002,215(1):85-92
For the first time the infrared spectrum of PHD2 was recorded in the region of the PH stretching fundamental ν1 at 2324.005 cm−1 and the overtone 2ν1 at 4563.634 cm−1 with a resolution of 4.2×10−3 cm−1 and 8.8×10−3 cm−1, respectively. In the analyses about 1340 and 1020 transitions were assigned to the corresponding ν1 and 2ν1 bands, which provided 316 and 248 upper energies, respectively. Since both the bands are sufficiently isolated, a standard Watson-type Hamiltonian (A-reduction, Ir-representation) was employed. The obtained sets of spectroscopic parameters correlate very well both with each other, and with the corresponding parameters of the ground vibrational state. 相似文献
15.
F. LattanziC. di Lauro M. HermanJ.Vander Auwera 《Journal of Molecular Spectroscopy》2002,216(2):308-314
A detailed investigation of the high-resolution infrared spectrum of ethane revealed the occurrence of features belonging to the hot perpendicular system (ν4+ν8)−ν4 between 1400 and 1510 cm−1. Transition lines of the subbranches with K″ΔK from −7 to 4, exhibiting torsional splittings of several tenths of a cm−1, were observed and measured in this region. The observed line splittings are strongly influenced by the interaction between the ν4+ν8 and 2ν4+ν12 states and change with the values of K″ΔK, depending on the zero-order energy separation of the interacting levels. We found by numerical extrapolation that splittings still occur far from resonance, showing that the intrinsic torsional splittings of the combining states ν4+ν8 and ν4 are quite different. We determined the intrinsic torsional splitting of ν4+ν8 to be less than 0.083 cm−1, compared with 0.236 cm−1 estimated for the ν4 state. This result is in agreement with the expected effects of torsional Coriolis and head-tail coupling and is consistent with previous observations on vibrationally degenerate states of ethane-like molecules. 相似文献
16.
Agnès Perrin Samir Kassi 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(15):2246-2255
The high-resolution absorption spectrum of the 4ν1+ν3 band of the 14N16O2 molecule was recorded by CW-Cavity Ring Down Spectroscopy between 6575 and 6700 cm−1. The assignments involve energy levels of the (4,0,1) vibrational state with rotational quantum numbers up to Ka=8 and N=48. A large majority of the spin-rotation energy levels were reproduced within their experimental uncertainty using a theoretical model which takes explicitly into account the Coriolis interactions between the spin-rotational levels of the (4,0,1) vibrational state and those of the (4,2,0) and of (0,9,0) dark states, the anharmonic interactions between the (4,2,0) and (0,9,0) states together with the electron spin-rotation resonances within the (4,0,1), (4,2,0) and (0,9,0) states. Precise vibrational energies, rotational, spin-rotational, and coupling constants were determined for the {(4,2,0), (0,9,0), (4,0,1)} triad of interacting states. Using these parameters and the value of the transition dipole-moment operator determined from a fit of a selection of experimental line intensities, the synthetic spectrum of the 4ν1+ν3 band was generated and is provided as Supplementary Material. 相似文献
17.
18.
M. Carlotti G. di Lonardo G. Galloni A. Trombetti 《Journal of Molecular Spectroscopy》1976,62(2):192-200
The infrared absorption of HNCO has been measured in the region of the NH stretching fundamental and in that of the second overtone. The results for the excited states are (in cm?1):
Band | B | C | ||
3533.1 | 27.0 | — | — | |
10145.79 | 22.6713 | 0.368426 | 0.361722 |