Line intensities in the ν1 + 2ν2, 2ν2 + ν3, 2ν1, ν1 + ν3, 2ν3, and ν1 + ν2 + ν3 − ν2 bands of H216O,between 6300 and 7900 cm−1

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%.     

High-resolution spectroscopy of difference and combination bands of SF6 to elucidate the ν3 + ν1 − ν1 and ν3 + ν2 − ν2 hot band structures in the ν3 region

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.     

High resolution FTIR spectra and analysis of the ν11 fundamental and of the ν2 + ν11, ν5 + ν12 and ν7 + ν16 combination bands of 12C6D6

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.     

First high-resolution analysis of the ν15, ν12, ν5, ν10 and ν2 bands of oxirane

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.     

Line intensities for the ν1, ν3 and ν1+ν3 bands of 34SO2

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.     

First high-resolution analysis of the ν1, ν3 and ν1 + ν3 bands of sulphur dioxide 33S16O2

• 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.

     

A simultaneous analysis of ν5, ν6, and the ground state of hydrazoic acid

The pure rotational spectrum in the vibrational ground state [J. Bendtsen and F. M. Nicolaisen, J. Mol. Spectrosc. 119, 456–466 (1986)] and the infrared spectrum of the fundamental bands ν₅ and ν₆ [J. Bendtsen, F. Hegelund, and F. M. Nicolaisen, J. Mol. Spectrosc. 118, 121–131 (1986)] of HN₃ have been simultaneously analyzed using a three-level model taking into account resonance between the ground state and ν₅ due to centrifugal distortion [K. Yamada, J. Mol. Spectrosc. 81, 139–151 (1980)] and a- and b-Coriolis interactions between ν₅ and ν₆. A set of ground- and upper-state constants have been obtained and values for the centrifugal distortion parameter C₅^ab and the Coriolis coupling constant ζ_5,6^b are derived. A complete set of ground-state energies for J ≦ 50 and K_a ≦ 10 is tabulated.     

Coriolis perturbations in the ν10, ν7, ν4, ν12 band system of trans-d2-ethylene

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.     

FTIR spectra and rovibrational analysis of parallel bands involving the ν1, ν2, and ν3 levels of natural and monoisotopic FClO3

Fourier Transform infrared spectra of gaseous natural FClO₃ and monoisotopic F³⁵ClO₃ have been recorded at 293 and 225 K with a resolution of 0.04 cm⁻¹. Rotational J structure and, in part, K structure were resolved for the parallel fundamentals, combination bands, and overtones ν₁, ν₂, ν₃, ν₁ + ν₂, ν₁ + ν₃, ν₂ + ν₃, 2ν₁, 2ν₂, and 2ν₃. Band origins ν₀, anharmonicity constants χ_ij, and vibration-rotation interaction constants α_i^A and α_i^B have been determined. For F³⁵ClO₃, ν₀ values are ν₁ = 1063.238(6), ν₂ = 716.814(6), and ν₃ = 549.877(3) cm⁻¹. No perturbation was found at the present level of accuracy.     

The ν6, ν8 3ν4+ν12 infrared system of Si2H6 under high resolution: rotational and torsional analysis

A Fourier transform infrared spectrum of disilane has been measured at a Doppler limited resolution, and analysed in the region of the ν₆ and ν₈ fundamentals, from about 800 to 1020cm^?1. The torsional splittings are not resolved in the ν₆ band, showing that the splittings in the ν₆ = 1 state and in the ground state are almost identical. The torsional splittings in the reasonably unperturbed regions of the ν₈ fundamental are about 0.0146cm^?1, and a detailed rotation-torsion analysis shows that the intrinsic splittings in the ν₈ = 1 state are smaller than in the ground state by this amount. An intrinsic torsional splitting about 0.0150 cm^?1 is estimated in the vibrational ground state and in the ν₆ = 1 state, and almost vanishing in the ν₈ = 1 state (about 0.0004cm^?1), with a barrier height around 407cm^?1. This is in agreement with the expectation from theory. The ν₈ band, beyond a moderate x, y-Coriolis coupling with ν₆, is affected by several perturbations, also selective in the torsional components. The 3ν₄ + v¹² combination, with three quanta of the torsional mode excited and large torsional splittings, is the main perturber, causing both Fermi and Coriolis resonances in several regions of the spectrum. The vibrational origins of all four torsional components of 3ν₄ + v¹² were determined. Other perturbative effects are attributed to the systems 2ν₃ + ν₄, and ν₄ + 24₉(E + A). The spectrum was numerically analysed, and the relevant vibration-rotation-torsion parameters were determined.     

High-resolution Fourier transform spectroscopy of the ν2 and ν3 fundamentals of nitrosyl fluoride,FNO

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

     

14.

Analysis of highly excited ‘hot’ bands in the SO2 molecule: ν2 + 3ν3 − ν2 and 2ν1 + ν2 + ν3 − ν2     

O.N. Ulenikov  E.S. Bekhtereva  O.V. Gromova  S. Alanko  V.-M. Horneman  C. Leroy 《Molecular physics》2013,111(10):1253-1261

     

15.

High-Resolution Analysis of the ν₆, ν₁₇, and ν₂₁ Bands of Dimethyl Ether     

L.H. CoudertP. Çarçabal  M. ChevalierM. Broquier  M. HeppM. Herman 《Journal of Molecular Spectroscopy》2002,212(2):203-207

The ν₆, ν₁₇, and ν₂₁ fundamental bands of dimethyl ether have been assigned and rotationally analyzed. The spectra used were recorded at 0.005 cm⁻¹ spectral resolution with a Fourier-transform spectrometer coupled to a supersonic molecular beam leading to a rotational temperature of about 70 K. The ν₆ and ν₂₁ bands do not seem to be perturbed and the analysis of the rotational structure leads to band centers located at 933.906 6(9) and 1 103.951(1) cm⁻¹, respectively, and to accurate rotational and centrifugal distortion constants. For the ν₁₇ band at 2817.385(2) cm⁻¹, only the P and R branches could be assigned.     

16.

Cyclopropane-d6: The C–D Stretching Bands ν6and ν8at High Resolution     

《Journal of Molecular Spectroscopy》1996,175(1):7-12

The two infrared active C–D stretching bands ν₆and ν₈of C₃D₆were recorded on a large Fourier transform spectrometer with a linewidth close to the Doppler–Fizeau limit. The perpendicular band of theE′ vibration ν₈near 2209.6 cm⁻¹is found to be highly perturbed by anharmonic resonances with the states ν₇+ 3ν₁₄, ν₇+ ν₉+ ν₁₄, and ν₄+ ν₁₀+ ν₁₄, and by aJ_x,yCoriolis-type interaction with an unidentified[formula]state. In contrast, the structure of the parallel band of the[formula]vibration ν₆near 2336.7 cm⁻¹appears to be relatively unperturbed. Spectroscopic constants are reported for the two fundamentals and for some of the perturbers of the ν₈state.     

17.

The ν6 infrared band of 1-phosphapropyne CH3CP     

《Journal of Molecular Spectroscopy》1987,126(2):245-254

The Fourier transform infrared spectrum of 1-phosphapropyne CH₃P was recorded in the region 1250–1550 cm⁻¹ at resolutions of 0.12 and 0.01 cm⁻¹. The ν₆^±1 band, centered at 1437.4748(29) cm⁻¹, was analyzed by taking account of a strong Coriolis interaction with ν₃ together with further Coriolis and Fermi interactions with ν₄ + 2ν₈^±2. On the basis of a Loomis-Wood diagram, 818 observed transitions with J ≤ 40 and K ≤ 9 have been assigned. A set of molecular constants was determined from a fit of the transitions with a rms error of 0.0037 cm⁻¹. A minor localized perturbation was also observed in the ^RR₂ branch and explained by a Coriolis interaction between ν₆^±1 and 2ν₄.     

18.

The ν1 and ν3 bands of 16O3: Line positions and intensities     

《Journal of Molecular Spectroscopy》1987,124(1):209-217

Using 0.005 cm⁻¹ resolution Fourier transform spectra of samples of ozone, the ν₁ and ν₃ bands of ¹⁶O₃ have been reanalyzed to obtain accurate line positions and an extended set of upper state rotational levels (J up to 69, K_a up to 20). Combined with the available microwave data, these upper state rotational levels were satisfactorily fitted using a Hamiltonian which takes explicitly into account the strong Coriolis interaction affecting the rotational levels of these two interacting states. In addition, 350 relative line intensities were measured from which the rotational expansions of the transition moment operators for the ν₁ and ν₃ states have been deduced. Finally, a complete listing of line positions, intensities, and lower state energies of the ν₁ and ν₃ bands of ¹⁶O₃ has been generated.     

19.

The ground and ν6=1 vibrational levels of HC35Cl3: The first high-resolution analysis of the ν6 fundamental band     

Petr Pracna  Adina Ceausu-Velcescu  Veli-Matti Horneman 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(11):1220-1225

     

20.

Observation of simultaneous ν₁(SF₆) + ν₃(NF₃) and ν₂(SF₆) + ν₃(NF₃) transitions enhanced by the resonance dipole-dipole interaction with the ν₁ + ν₃ and ν₂ + ν₃ states of the SF₆ molecule     

V. N. Bocharov  A. P. Burtsev  E. V. Dubrovskaya  T. D. Kolomiitsova  D. N. Shchepkin 《Optics and Spectroscopy》2010,108(4):533-543

IR spectra of the solution of SF₆ molecules in liquid NF₃ at 84 K have been recorded. In a solvent transmission window of 1500–1750 cm⁻¹, two wide absorption bands with pronounced peaks in the high-frequency part are observed. The profile of these bands is explained by the influence of the resonance dipole-dipole (RDD) interaction of the states of the simultaneous transition ν₁(SF₆) + ν₃(NF₃) and ν₂(SF₆) + ν₃(NF₃) with the states (ν₁ + ν₃) and (ν₂ + ν₃) of the SF₆ molecules, respectively. The use of three isotopic modifications ³²SF₆, ³³SF₆, and ³⁴SF₆ has allowed us to vary the resonance detuning and thus to change the strength of the RDD interaction. With the liquid near the melting point being represented as a close-packed cubic crystal, the profile was calculated and its spectral characteristics were determined. The frequencies of the main peaks coincide with the experimental values accurate to the error.     

	Ground state	$\text{ν}{}_2$	$\text{ν}{}_3$
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)
$\text{ν}{}_0$	0	765.3551 (4)	519.5980 (4)

High-Resolution Analysis of the ν6, ν17, and ν21 Bands of Dimethyl Ether

The ν₆, ν₁₇, and ν₂₁ fundamental bands of dimethyl ether have been assigned and rotationally analyzed. The spectra used were recorded at 0.005 cm⁻¹ spectral resolution with a Fourier-transform spectrometer coupled to a supersonic molecular beam leading to a rotational temperature of about 70 K. The ν₆ and ν₂₁ bands do not seem to be perturbed and the analysis of the rotational structure leads to band centers located at 933.906 6(9) and 1 103.951(1) cm⁻¹, respectively, and to accurate rotational and centrifugal distortion constants. For the ν₁₇ band at 2817.385(2) cm⁻¹, only the P and R branches could be assigned.     

Cyclopropane-d6: The C–D Stretching Bands ν6and ν8at High Resolution

The two infrared active C–D stretching bands ν₆and ν₈of C₃D₆were recorded on a large Fourier transform spectrometer with a linewidth close to the Doppler–Fizeau limit. The perpendicular band of theE′ vibration ν₈near 2209.6 cm⁻¹is found to be highly perturbed by anharmonic resonances with the states ν₇+ 3ν₁₄, ν₇+ ν₉+ ν₁₄, and ν₄+ ν₁₀+ ν₁₄, and by aJ_x,yCoriolis-type interaction with an unidentified[formula]state. In contrast, the structure of the parallel band of the[formula]vibration ν₆near 2336.7 cm⁻¹appears to be relatively unperturbed. Spectroscopic constants are reported for the two fundamentals and for some of the perturbers of the ν₈state.     

The ν6 infrared band of 1-phosphapropyne CH3CP

The Fourier transform infrared spectrum of 1-phosphapropyne CH₃P was recorded in the region 1250–1550 cm⁻¹ at resolutions of 0.12 and 0.01 cm⁻¹. The ν₆^±1 band, centered at 1437.4748(29) cm⁻¹, was analyzed by taking account of a strong Coriolis interaction with ν₃ together with further Coriolis and Fermi interactions with ν₄ + 2ν₈^±2. On the basis of a Loomis-Wood diagram, 818 observed transitions with J ≤ 40 and K ≤ 9 have been assigned. A set of molecular constants was determined from a fit of the transitions with a rms error of 0.0037 cm⁻¹. A minor localized perturbation was also observed in the ^RR₂ branch and explained by a Coriolis interaction between ν₆^±1 and 2ν₄.     

The ν1 and ν3 bands of 16O3: Line positions and intensities

Using 0.005 cm⁻¹ resolution Fourier transform spectra of samples of ozone, the ν₁ and ν₃ bands of ¹⁶O₃ have been reanalyzed to obtain accurate line positions and an extended set of upper state rotational levels (J up to 69, K_a up to 20). Combined with the available microwave data, these upper state rotational levels were satisfactorily fitted using a Hamiltonian which takes explicitly into account the strong Coriolis interaction affecting the rotational levels of these two interacting states. In addition, 350 relative line intensities were measured from which the rotational expansions of the transition moment operators for the ν₁ and ν₃ states have been deduced. Finally, a complete listing of line positions, intensities, and lower state energies of the ν₁ and ν₃ bands of ¹⁶O₃ has been generated.     

Observation of simultaneous ν1(SF6) + ν3(NF3) and ν2(SF6) + ν3(NF3) transitions enhanced by the resonance dipole-dipole interaction with the ν1 + ν3 and ν2 + ν3 states of the SF6 molecule

IR spectra of the solution of SF₆ molecules in liquid NF₃ at 84 K have been recorded. In a solvent transmission window of 1500–1750 cm⁻¹, two wide absorption bands with pronounced peaks in the high-frequency part are observed. The profile of these bands is explained by the influence of the resonance dipole-dipole (RDD) interaction of the states of the simultaneous transition ν₁(SF₆) + ν₃(NF₃) and ν₂(SF₆) + ν₃(NF₃) with the states (ν₁ + ν₃) and (ν₂ + ν₃) of the SF₆ molecules, respectively. The use of three isotopic modifications ³²SF₆, ³³SF₆, and ³⁴SF₆ has allowed us to vary the resonance detuning and thus to change the strength of the RDD interaction. With the liquid near the melting point being represented as a close-packed cubic crystal, the profile was calculated and its spectral characteristics were determined. The frequencies of the main peaks coincide with the experimental values accurate to the error.