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1.
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
2.
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
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.
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
5.
《Journal of Molecular Spectroscopy》1987,123(2):255-266
The vibration-rotation spectrum of the ν6 fundamental band of carbonyl fluoride (COF2) has been recorded at room temperature and 0.005 cm−1 resolution, using a Fourier transform spectrometer. Although the strong Q branch at 774 cm−1 is only partially resolved in the spectrum, most of the K structure of various J subgroups in the P and R branches has been fully resolved. More than 1500 transitions belonging to J values up to 40 have been assigned and simultaneously fitted with the microwave frequencies reported by J. H. Carpenter [J. Mol. Spectrosc. 50, 182–201 (1974)] with a standard deviation of 0.0006 cm−1. By incorporating quartic and sextic centrifugal distortion coefficients in Watson's reduced Hamiltonian in the Ir representation, upper state rotational constants A, B, and C have been determined to an accuracy better than 10−5 cm−1. Ground state rotational and fourth order centrifugal distortion constants were constrained in the analysis to the values reported by W. Lewis-Bevan et al. [J. Mol. Spectrosc. 113, 458–471 (1985)]. 相似文献
6.
《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
7.
《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
8.
Russian Physics Journal - The intensities of 740 vibrational-rotational lines of the ν9 fundamental band in the IR spectrum of the trans-C2H2D2 molecule are first analyzed. The... 相似文献
9.
《Journal of Molecular Spectroscopy》1986,118(2):530-539
The infrared diode laser spectrum of the ν6 + ν8 band of diacetylene (HCCCCH), i.e., a combination band of symmetric πg (ν6) and antisymmetric πu (ν8) CCH bending vibrations, was recorded by the Stark and source modulation techniques. The analysis of the Stark modulation spectrum allowed us to locate the 2ν6 (Σg+) and 2ν8 (Σg+) vibrational states, which are inaccessible by infrared transitions from the ground state. It is also shown that the Stark modulation spectrum can be used to confirm the rotational assignment of the ν6 + ν8 band. 相似文献
10.
Russian Physics Journal - The ν2 + ν10 (Bu) hybrid band of the trans-C2H2D2 molecule in the region 2100–2300 cm–1 is studied for the first time. The spectrum has been analyzed... 相似文献
11.
O.N. Ulenikov G.A. Onopenko E.S. Bekhtereva T.M. Petrova A.M. Solodov A.A. Solodov 《Molecular physics》2013,111(5):637-647
The combination band ν5 + ν12 of ethylene, C2H4, has been recorded for the first time with a high resolution Fourier transform spectrometer Bruker IFS 125HR. Assignments of transitions and preliminary rotational analysis are made. Two models (Hamiltonian of the isolated vibrational state and Hamiltonian that takes into account resonance interactions) are used. Influence of the local resonance interactions on the parameters and reproduction power of the models is discussed. 相似文献
12.
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.
13.
《Journal of Molecular Spectroscopy》1987,126(2):270-281
The ν1 (FS stretch) and ν3 (SN stretch) bands of FSN have been measured with Dopplerlimited resolution using a diode laser spectrometer. An accurate set of band constants were determined for ν1 from a simultaneous fit to 265 infrared data and 73 ground state rotational transitions. The ν3 band was found to be perturbed as the result of a Coriolis-type interaction between the states (0, 0, 1) and (1, 2, 0). Further difficulties with ν3 were produced by the presence of many strong absorption lines from an SO2 impurity. A limited set of effective band constants were determined for this band. Some general aspects of Q-branch absorption line patterns are briefly discussed. 相似文献
14.
The ν2 and ν3 fundamentals of FNO have been recorded with a Fourier transform spectrophotometer at an apodized resolution of approximately 0.004 cm?1. The Fourier infrared data have been analyzed together with previous microwave data to yield improved molecular parameters for the (000) and (010) vibrational states and the first set of constants for the (001) state. The main results (in cm?1) are
Ground state | |||
A | 3.1751882 (17) | 3.1861249 (12) | 3.1958722 (15) |
B | 0.39508266 (12) | 0.39407878 (14) | 0.39211484 (14) |
C | 0.35051504 (11) | 0.34899779 (16) | 0.34747411 (14) |
0 | 765.3551 (4) | 519.5980 (4) |