Pressure Broadening and Temperature Dependence of Microwave and Far Infrared Rotational Lines in OH Perturbed by N2, O2, and Ar

Benec'h, S.; Buldyreva, J.; Chrysos, M.

doi:10.1006/jmsp.2001.8457

Cited by 11 publications

(7 citation statements)

References 26 publications

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“…It has commonly been argued that the larger absolute magnitude of the quadrupole moment of N 2 compared to O 2 is responsible for the larger cross sections in a variety of related phenomena, including the inelastic contribution to line broadening. 42,43 This straightforward long-range attractive-force argument might also be invoked to rationalize our results for CN(A) here. However, the basis of such an analysis has been questioned in systems such as OH(X) with N 2 and O 2 , where rigorous calculations indicate a significantly deeper interaction with O 2 .…”

Section: Discussionsupporting

confidence: 75%

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Parity-Dependent Rotational Energy Transfer in CN(A²Π, ν = 4, j F₁ε) + N₂, O₂, and CO₂ Collisions

et al. 2014

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We report state-resolved total removal cross sections and state-to-state rotational energy transfer (RET) cross sections for collisions of CN(A2Π, ν = 4, jF1ε) with N2, O2, and CO2. CN(X2Σ+) was produced by 266 nm photolysis of ICN in a thermal bath (296 K) of the collider gas. A circularly polarized pulse from a dye laser prepared CN(A2Π, ν = 4) in a range of F1e rotational states, j = 2.5, 3.5, 6.5, 11.5, 13.5, and 18.5. These prepared states were monitored using the circularly polarized output of an external cavity diode laser by frequency-modulated (FM) spectroscopy on the CN(A–X)(4,2) band. The FM Doppler profiles were analyzed as a function of pump–probe delay to determine the time dependence of the population of the initially prepared states. Kinetic analysis of the resulting time dependences was used to determine total removal cross sections from the initially prepared levels. In addition, a range of j′ F1e and j′ F2f product states resulting from rotational energy transfer out of the j = 6.5 F1e initial state were probed, from which state-to-state RET cross sections were measured. The total removal cross sections lie in the order CO2 > N2 > O2, with evidence for substantial cross sections for electronic and/or reactive quenching of CN(A, ν = 4) to unobserved products with CO2 and O2. This is supported by the magnitude of the state-to-state RET cross sections, where a deficit of transferred population is apparent for CO2 and O2. A strong propensity for conservation of rotational parity in RET is observed for all three colliders. Spin–orbit-changing cross sections are approximately half of those of the respective conserving cross sections. These results are in marked disagreement with previous experimental observations with N2 as a collider but are in good agreement with quantum scattering calculations from the same study (Khachatrian19215110J. Phys. Chem. A20091133922). Our results with CO2 as a collider are similarly in strong disagreement with a related experimental study (Khachatrian19405498J. Phys. Chem. A200911313390). We therefore propose that the previous experiments substantially underestimated the spin–orbit-changing cross sections for collisions with both N2 and CO2, suggesting that even approximate quantum scattering calculations may be more successful for such molecule–molecule systems than was previously concluded.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Parity-Dependent Rotational Energy Transfer in CN(A²Π, ν = 4, j F₁ε) + N₂, O₂, and CO₂ Collisions

et al. 2014

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“…(48) Theoretical RBE computations of rotational and vibrotational line-broadening coefficients for the OH-N 2 , OH-O 2 and OH-Ar systems were made in Ref. [237] for temperatures of 194, 200, 296 and 300 K (Tables 4.57, 4.58); the interaction potential parameters for these systems are given in Appendix B). …”

Section: Oh Moleculementioning

confidence: 99%

“…RBE-calculated OH-N 2 line-broadening coefficients (in 10 -3 cm -1 atm -1 )[237].Table 4.58. RBE [237] and experimental [231, 232] ОН-O 2 coefficients γ (in 10 -3 cm -1 atm -1 ).…”

mentioning

confidence: 99%

Pressure broadening and shifting of vibrotational lines of atmospheric gases

Buldyreva¹,

Lavrentieva²,

Starikov³

2010

Collisional Line Broadening and Shifting of Atmospheric Gases

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Water vapour is one of the strongest absorbers of radiation in the Earth's atmosphere, but some other gases also play an important role in the atmospheric radiative transfer processes: carbon dioxide CO 2 , carbon monoxide CO, ozone О 3 , methane CH 4 . Minor atmospheric pollutants such as hydrogen sulphide H 2 S, methyl fluoride CH 3 F, methyl chloride CH 3 Cl, ethylene C 2 H 4 , nitric oxide NO, nitrous oxide N 2 O and nitrogen dioxide NO 2 are equally recognised for their implication in the fundamental chemical reactions occurring in the terrestrial atmosphere. As a consequence, a lot of spectroscopic studies are made for these molecules in order to obtain the line positions, intensities and widths. They are briefly summarised below, starting by asymmetric waterlike molecules of X 2 Y-type which have the same selection rules for vibrotational spectra. Vibrotational lines of asymmetric X 2 Y moleculesBetween asymmetric tops of the X 2 Y type most attention in the spectroscopic literature is paid to the H 2 S, SO 2 , O 3 and NO 2 molecules. _________________________________________________________________ A vibrotational state (v 1 v 2 v 3 ) [J K a K c ] of these molecules is characterised by three vibrational quantum numbers v 1 , v 2 , v 3 and three rotational quantum numbers J, K a , K c . In the NO 2 molecule, having an unpaired electron (total electronic spin S = 1/2), each vibrotational level is split by the spin-rotational interaction into two components (J = N ± S) denoted by + or -, and the three rotational quantum numbers are N, K a , K c . For a given set of vibrotational quantum numbers the corresponding energies are obtained by a diagonalization of the effective Hamiltonian matrix of Eq. (3.

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“…Buffa et al [14] have employed Anderson theory to compute line shapes in collisions with N 2 . Benećh et al [15] used a semiclassical formalism with PES's composed of long-and short-range contributions to calculate temperature-dependent linewidths for Λ-doublet and pure rotational transitions in collisions with N 2 , O 2 , and Ar.…”

Section: Introductionmentioning

confidence: 99%

Pressure broadening calculations for OH in collisions with argon: Rotational, vibrational, and electronic transitions

Dagdigian

2017

Journal of Quantitative Spectroscopy and Radiative Transfer

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Collisional parameters describing both the pressure-induced broadening and shifting of isolated lines in the spectrum of the hydroxyl radical in collisions with argon have been determined through quantum scattering calculations using accurate potential energy surfaces describing the OH(X 2 Π,A 2 Σ + )-Ar interactions. These calculations have been carried for pure rotational, vibrational, and electronic transitions. The calculated pressure broadening coefficients are in good agreement with the available measurements in the microwave, infrared, and ultraviolet spectral regions. Computed pressure broadening coefficients as a function of temperature are reported for these three types of transitions.

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Pressure Broadening and Temperature Dependence of Microwave and Far Infrared Rotational Lines in OH Perturbed by N2, O2, and Ar

Cited by 11 publications

References 26 publications

Parity-Dependent Rotational Energy Transfer in CN(A²Π, ν = 4, j F₁ε) + N₂, O₂, and CO₂ Collisions

Parity-Dependent Rotational Energy Transfer in CN(A²Π, ν = 4, j F₁ε) + N₂, O₂, and CO₂ Collisions

Pressure broadening and shifting of vibrotational lines of atmospheric gases

Pressure broadening calculations for OH in collisions with argon: Rotational, vibrational, and electronic transitions

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Pressure Broadening and Temperature Dependence of Microwave and Far Infrared Rotational Lines in OH Perturbed by N2, O2, and Ar

Cited by 11 publications

References 26 publications

Parity-Dependent Rotational Energy Transfer in CN(A2Π, ν = 4, j F1ε) + N2, O2, and CO2 Collisions

Parity-Dependent Rotational Energy Transfer in CN(A2Π, ν = 4, j F1ε) + N2, O2, and CO2 Collisions

Pressure broadening and shifting of vibrotational lines of atmospheric gases

Pressure broadening calculations for OH in collisions with argon: Rotational, vibrational, and electronic transitions

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Parity-Dependent Rotational Energy Transfer in CN(A²Π, ν = 4, j F₁ε) + N₂, O₂, and CO₂ Collisions

Parity-Dependent Rotational Energy Transfer in CN(A²Π, ν = 4, j F₁ε) + N₂, O₂, and CO₂ Collisions