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1.
J.-M. Flaud W.J. Lafferty F. Kwabia Tchana A. Perrin X. Landsheere 《Journal of Molecular Spectroscopy》2012,271(1):38-43
Fourier transform spectra of oxirane (ethylene oxide, c-C2H4O) have been recorded in the 730–1560 cm?1 (6.4–13.7 μm) spectral region using a Bruker IFS125HR spectrometer at a resolution of 0.0019 cm?1. A total of six vibration bands, ν15, ν12, ν5, ν3, ν10 and ν2, have been observed and analyzed. The corresponding upper state ro-vibrational levels were fit using Hamiltonian matrices accounting for various interactions. Satisfactory fits were obtained using the following polyads {151, 121, 51} and {101, 21} of interacting states. As a result, an accurate and extended set of Hamiltonian constants were obtained. The following band centers were derived: ν0 (ν15) = 808.13518(60) cm?1, ν0 (ν12) = 822.27955(37) cm?1, ν0 (ν5) = 876.72592(15), ν0 (ν3) = 1270.37032(10) cm?1, ν0 (ν10) = 1471.35580(50) cm?1 and ν0 (ν2) = 1497.83309(15) cm?1 where the uncertainties are one standard deviation. 相似文献
2.
The strong infrared absorption in the ν3 S–F stretching region of sulphur hexafluoride (SF6) near 948 cm?1 makes it a powerful greenhouse gas. Although its present concentration in the atmosphere is very low, it is increasing rapidly, due to industrial pollution. The ground state population of this heavy species is only 32% at room temperature and thus many hot bands are present. Consequently, a reliable remote-sensing spectroscopic detection and monitoring of this species require an accurate modelling of these hot bands. We used two experimental set-ups at the SOLEIL French synchrotron facility to record some difference and combination bands of SF6: (1) a new cryogenic multiple pass cell with 93 m optical path length and regulated at 163 ± 2 K temperature and (2) the Jet-AILES supersonic expansion set-up. With this, we could obtain high-resolution absorption spectra of the ν3 ? ν1, ν3 ? ν2, ν1 + ν3 and ν2 + ν3 bands at low temperature. These spectra could be assigned and analysed, thanks to the SPVIEW and XTDS computer programs developed in Dijon. We performed two global fits of effective Hamiltonian parameters. The first one is a global fit of the ground state, ν2, ν3, ν3 ? ν2, ν2 + ν3, 2ν3 and 2ν3 ? ν3 rovibrational parameters, using the present spectra and previous infrared, Raman and two-photon absorption data. This allows a consistent refinement of the effective Hamiltonian parameters for all the implied vibrational levels and a new simulation of the 2ν3 + ν2 ? ν2 hot band. The second global fit involves the present ν3 ? ν1 and ν1 + ν3 lines, together with previous ν1 Raman data, in order to obtain refined ν1 parameters and also ν1 + ν3 parameters in a consistent way. This allows to simulate the ν3 + ν1 ? ν1 hot band. 相似文献
3.
MARCEL SNELS HANS HOLLENSTEIN MARTIN QUACK ELISABETTA CANÉ ANDREA MIANI AGOSTINO TROMBETTI 《Molecular physics》2013,111(7):981-1001
We report results from measurements of the high resolution FTIR spectrum for the fully deuterated benzene molecule C6D6 in the range 450–3500 cm?1. Accurate spectroscopic constants have been obtained for the fundamental vibration ν11 at 496.208 cm?1 and improved ground state constants have been deduced from a fit of ground state combination differences. The J structure of the combination parallel bands ν2 + ν11 (at 2798.1 cm?1), ν5 + ν12 (1802.5 cm?1) and ν7, + ν16 (2619.3 cm?1) of C6D6 has been analysed as well, from which improved values of the band origin and of the B and D j constants of the excited states have been obtained. The strongest hot bands accompanying these parallel transitions have been assigned by means of the anharmonic force field calculated by Maslen et al. [1992, J. chem. Phys., 97, 4233]. In particular (ν11 + ν16) ? ν16 is assigned to the band at 492.4 cm?1 even though its shape is typical of a perpendicular transition (PAPE). New values for the ν5, ν12 and ν16 band origins are determined from the band origins of combination bands and from calculated anharmonic constants. Numerous anharmonic constants are derived from the assignment of hot band and combination transitions. 相似文献
4.
《Journal of Molecular Spectroscopy》1986,116(1):214-227
The effect of a-, b-, and c-axis Coriolis perturbations in the infrared spectrum of the band system ν10, ν7, ν4, ν12 of trans-d2-ethylene has been studied at a resolution near 0.03 cm−1. From a global analysis of this band system taking into account Coriolis resonances, spectroscopic constants for each of the vibrations are derived as well as second-order Coriolis interaction constants for ν10 and ν7. 相似文献
5.
6.
High-resolution spectra of 33S16O2 have been recorded for the first time in the 8 and 4 µm spectral regions.
The ν1, ν3 and ν1 + ν3 bands of the 33S16O2 have been analysed up to very high quantum numbers.
Accurate ro-vibrational upper states constants have been determined.
7.
《Journal of Molecular Spectroscopy》1986,118(1):96-102
Using Fourier transform spectra, the intensities of 428 weak lines belonging to the ν1 + 2ν2, 2ν2 + ν3, 2ν1, ν1 + ν3, 2ν3, and ν1 + ν2 + ν3 − ν2 bands of the H216O molecule have been measured, between 6300 and 7900 cm−1, with an average uncertainty of 7%. 相似文献
8.
Vibration-rotation spectra of the ν2 and ν4 bands of CH4 have been analysed by a simultaneous diagonalization of the hamiltonian matrices for the v 2=1 and v 4=1 states coupled by the Bξ2,4 Coriolis interaction term. The effective hamiltonians used extend to sextic centrifugal distortion terms. The results are a significant improvement on any previous analysis; 438 assigned transitions up to J′=16 have been fitted with an overall standard deviation of 0·016 cm-1. The method used is compared with an alternative theoretical approach given by Berger. 相似文献
9.
10.
J.-M. Flaud W.J. Lafferty R.L. Sams 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(9-10):669-674
Using both high resolution (0.0018 cm?1) and medium resolution (0.112 cm?1) Fourier transform spectra of an enriched 34S (95.3%) sample of sulfur dioxide, it has been possible to accurately measure a large number of individual line intensities for some of the strongest of the SO2 bands, i.e. ν1, ν3 and ν1+ν3. These intensities were least-squares fitted using a theoretical model which takes into account the vibration–rotation interactions linking the upper energy levels where needed, and, in this way, expansions of the various transition moment operators were determined. The Hamiltonian parameters determined in previous analyses together with these moments were then used to generate synthetic spectra for the bands studied and their corresponding hot bands providing one with an extensive picture of the absorption spectrum of 34SO2 in the spectral domains, 8.7, 7.4, and 4 μm. 相似文献
11.
《Journal of Molecular Spectroscopy》1987,126(1):149-158
The absorption of 12CH3D at 6–10 μm was recorded under vacuum with a resolution of 0.0054 cm−1. For the first time the ν5 band was assigned extensively, allowing the analysis of ν3, ν5, and ν6 together within a “triad model,” including a rigorous treatment of all the Coriolis couplings involved. The assignments in the spectral range were anlarged from the original 1000 to the present 3500. The newly assigned lines essentially concerned the ν5 band and a great number of perturbation-allowed transitions (about 30% of all observations). Ground state energy parameters were refined from 2641 combination differences involving J up to 19 and |ΔK| up to 6; the standard deviation of the fit was 0.0003 cm−1. A set of 35 triad upper state energy parameters was derived, reproducing all observations with a standard deviation of 0.0076 cm−1. The three dipole moment derivatives involved in the intensity calculations were estimated theoretically, by taking advantage of the recent accurate determination of the band strengths S3 and S4 of 12CH4. Finally, about 6000 triad transitions predicted with linestrengths at least equal to 4 × 10−25 cm·molecule−1 were tabulated with assignments, wavenumbers, linestrengths, and lower and upper energy levels. 相似文献
12.
《Journal of Molecular Spectroscopy》1986,118(1):121-131
The infrared absorption spectrum of the ν5 and ν6 fundamentals of HN3 has been measured with a resolution of 0.03 cm−1. The spectrum has been analyzed taking into account the first- and second-order a-type Coriolis resonance between the two vibrations. Constraining the value for the ζ constant and the ground state parameters the analysis yields values for the rotational constants for both bands. 相似文献
13.
The infrared vibration-rotation spectrum of formaldehyde vapor has been measured in the region from 2600 to 3400 cm?1 with resolution from 0.04 to 0.07 cm?1. An extensive rotational analysis of the ν1 and ν5 bands has confirmed and superseded the previous band-contour analysis of a medium-resolution spectrum. A large number of subbranches of both the ν1 and ν5 bands are perturbed by the combination bands ν3 + ν6, ν2 + ν4, and ν2 + ν6, whereas the Coriolis interaction between ν1 and ν5 is weak. The following effective rotational constants (in cm?1) are obtained: , , where the number given in parentheses is three times the standard error in the last digit. 相似文献
14.
Using CO2 and N2O lasers, we have measured and assigned nineteen ν4 and nine ν6 rotation-vibration resonances of the type ΔM = 0 and M = J. These transitions were combined with the zero-field pure rotational spectra in order to determine the two fundamental vibrational frequencies, the rotational constants of both excited states, the Coriolis coupling constant, and the dipole moments of each of the three states. The ground-state rotational constants and centrifugal distortion constants were taken from a microwave study and the centrifugal distortion constants of the excited states were assumed equal to those of the ground state. The following results were obtained (standard deviations in parentheses):
938.0345 (6) | 989.2519 (18) | (cm?1) | ||||
139 579 (150) | 143 323 (150) | (MHz) | ||||
31 873.6 (5) | 32 379.5 (7) | (MHz) | ||||
26 242.9 (6) | 25 994.4 (8) | (MHz) | ||||
136 178 (770) | (MHz) | |||||
μ | 2.319 (10) | 2.347 (4) | (D) | |||
μ(ground state) | 2.3464 (8) | (D) |