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1.
In a recent theoretical paper, vibrational frequencies were reported for CBrCl in the and à states. These values agree well with our previously published experimental frequencies, except in the case of , where the theoretical value of 968.3 cm−1 is significantly higher than the experimental value of 712.6 cm−1. This discrepancy prompted a re-examination of the assignments for transitions involving ν1 in the laser induced fluorescence spectrum. If the progression ν1 + 2 has the assignment of n reduced by 1 (the origin is not observed), a new experimental value of results. The close accord with the theoretical value lends weight to this re-assignment. Consequently we propose that the experimental frequency be changed to .  相似文献   

2.
Infrared spectrum of the cobalt carbonyl radical CoCO produced by the 193 nm excimer laser photolysis of cobalt tricarbonyl nitrosyl Co(CO)3NO was observed by time-resolved diode laser spectroscopy. More than 600 lines were identified as belonging to the ν1 (C-O stretch) fundamental band, consisting of the Ω=5/2 and 3/2 subbands, and the associated hot bands , , , and . The 2Δi electronic ground state of CoCO was experimentally confirmed. The ν1 band origins are 1974.172582(93) cm−1 and 1973.53178(14) cm−1 for the Ω=5/2 and 3/2 subbands, respectively. The rotational constant in the ground state was determined as B0=4427.146(50) MHz. The centrifugal distortion constant D0=1.1243(68) kHz was obtained for the Ω=5/2 substate of the ground state. The equilibrium rotational constant Be=4435.44(14) MHz was derived, together with the vibration-rotation interaction constants.  相似文献   

3.
4.
The intracavity laser absorption spectra (ICLAS) of dideuteroacetylene, C2D2, and acetylene, C2H2, have been recorded between 1.03 and 0.99 μm with a vertical external cavity surface emitting laser (VECSEL) leading to the observation of seven and six bands, for C2D2 and C2H2 respectively, most of them newly reported. The strong ν1+3ν3 band of C2D2 at is found accompanied by the two Π-Π hot bands with v4=1 and v5=1 lower state and by the ν2+3ν3+2ν4 band near . This last band results from an intensity transfer from the ν1+3ν3 band induced by the 1/244 anharmonic interaction. The ν1+3ν3 band of , present in natural abundance in the sample, could also be detected at in full agreement with local mode model predictions. The different bands of both C2H2 and C2D2 were found mostly unperturbed and the spectroscopic parameters retrieved from the rovibrational analyses agree satisfactorily with the predictions of the respective effective Hamiltonian models.  相似文献   

5.
Absorption lines of 12C16O2 have been examined by using a tunable diode laser spectrometer in the region around (790 nm). The spectrometer sources are commercially available double heterostructure InGaAlAs tunable diode lasers (TDLs) operating in the “free-running” mode, which allowed the detection of the line positions within . The observed carbon dioxide absorption lines belong to the combination overtone 2ν2+5ν3 ro-vibrational band with intensities ranging around .  相似文献   

6.
High-resolution infrared spectra of boron trifluoride, enriched to 99.5 at. % 11B, have been measured from 400 to 1650 cm−1. In that region we have identified and analyzed 16 absorption bands attributed to the three fundamental bands, two combination bands, 10 hot bands, and one difference band. All possible states were accessed in this region through direct transitions either from the ground state or as hot bands from thermally populated levels. The spectral resolution of the measurements varied from 0.0015 to 0.0020 cm−1. An improved set of ground state rotational constants and rovibrational constants for the infrared-active fundamental vibrations have been determined from over 32 000 assigned transitions. This study resulted in the first direct characterization of the infrared-inactive ν1 state of 11BF3 leading to values for ν1, , and of 885.843205(24), 0.000678548(53), and 0.000337564(66) cm−1, respectively. The Fermi resonance perturbation between the E′ states ν3 and 3ν4 (l = ±1) was further elucidated by observation of hot band transitions to both the 3ν4 (l = ±1) and 3ν4 (l = ±3) states. Several other resonances were also found including the weak rotational interaction, between the state 2ν2 and the E′ state of ν1 + ν4.  相似文献   

7.
The high resolution infrared spectrum of mono-isotopic F37Cl16O3 has been studied in the regions of ν1, ν2, ν4 and ν2 + ν5 bands, centered at 1060.20, 707.16, 1301.71 and 1292.15 cm−1, respectively. The ν1 and ν2 parallel bands are unperturbed so their analysis was straightforward and 3355 and 2433 transitions were assigned, respectively. The band origins, the rotational and centrifugal molecular constants in the v1 = 1 and v2 = 1 states have been determined, with standard deviation of the fits σ = 0.00019 and 0.00018 cm−1. The ν4 fundamental is affected by an anharmonic resonance with the ν2 + ν5 combination band. The kl > 0 sublevels cross at kl ? 27 because of the opposite values of and . The anharmonic resonance constant  cm−1 has been derived. The Δl = Δk = ±2 and Δl = 0, Δk = ±3 essential resonances have been found to be effective in ν4, while in ν2 + ν5 only the Δl = Δk = ±2 one was active. A total of 5721 transitions have been assigned, 25% of them belonging to ν2 + ν5. The rovibrational parameters and the interaction constants of F37Cl16O3 have been obtained. The standard deviation of the fit is 0.0006 cm−1, six times the estimated data precision. The equilibrium geometry of perchloryl fluoride has been determined from the Ae and Be constants of F35Cl16O3 and F37Cl16O3. Using the A0 and B0 constants of all the symmetric species the r0 geometry has also been derived.  相似文献   

8.
9.
The O-H stretching overtone (2ν1) of the HO2 radical was observed between 6603.2 to by using tunable diode laser absorption spectroscopy (TDLAS). About 1000 lines were observed in this region of which 491 transitions could be definitively assigned to the 2ν1. The spectrum is observed to be an A/B hybrid band with band features of both a perpendicular and parallel nature. Transitions of the A-type bands with Ka=0-3, N?16 and transitions of the B-type bands with Ka=0,1, N?15 were assigned. The origin calculated from the best fit to the present spectrum is at which is ∼ higher than previously reported. The overtone spectrum is observed to be heavily perturbed, possibly by Fermi resonance with energy levels of the nearby (ν2+5ν3) state.  相似文献   

10.
The high-resolution infrared spectrum of deuterated fluoroform (DCF3) was studied in the 700 and 1200 cm−1 regions, with the aim of assigning and analyzing the ν4 CF3 asymmetric stretching vibration. The Fermi-type anharmonic coupling between the ν4 = 1 and ν3 = ν6 = 1 rovibrational levels, already mentioned in an early work of Ruoff et al. [Spectrochimica Acta Part A 31A (1975) 1099-1100], was studied here for the first time under high resolution. Assignments in the ν3 + ν6/ν4 band system were confirmed and extended by the identification of the ν3 + ν6 − ν6 and ν4-ν6 bands in the 700 cm−1 region, the latter being enhanced near the Fermi crossings of the studied levels. Data from both the hot and difference bands were included in the analysis. The close separation of the studied vibrational levels of about 14.8 cm−1 produces a large variety of resonance crossings which involve levels with . Besides the Fermi () and Coriolis () resonances, they were accounted for by inclusion of additional higher-order ( and ) interaction terms between the vibrational states. The least-squares fit of more that 16,000 vibration-rotation transitions provides a quantitative reproduction of data in all bands.  相似文献   

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