Speed-dependent pressure broadening and shift in the soft collision approximation

Ciuryło, R.; Szudy, J.

doi:10.1016/s0022-4073(96)00078-7

Cited by 132 publications

(89 citation statements)

References 24 publications

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“…(5) development. Moreover, () has an analytical form for a number of line profiles such as Voigt, Galatry, Speed-Dependent Voigt and Speed-Dependent Galatry models [12,[26][27][28][29], including the case of frequency modulated spectral profiles [30]. Of course, the result is not restricted to the 2 nd order low pass filters (or to the 1 st order ones by setting Q = 0), and can be generalized to more complicated detection schemes.…”

Section: B Impact Of the Detection Bandwidth On Recorded Dipole Momementioning

confidence: 99%

Absorption-line-shape recovery beyond the detection-bandwidth limit: Application to the precision spectroscopic measurement of the Boltzmann constant

et al. 2014

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A theoretical model of the influence of detection bandwidth properties on observed line shapes in laser absorption spectroscopy is described. The model predicts artificial frequency shifts, extra broadenings and line asymmetries which must be taken into account in order to obtain accurate central frequencies and other spectroscopic parameters. This reveals sources of systematic effects most probably underestimated so far potentially affecting spectroscopic measurements. This may impact many fields of research, from atmospheric and interstellar physics to precision spectroscopic measurements devoted to metrological applications, tests of quantum electrodynamics or other fundamental laws of nature. Our theoretical model is validated by linear absorption experiments performed on H 2 O and NH 3 molecular lines recorded by precision laser spectroscopy in two distinct spectral regions, nearand mid-infrared. Possible means of recovering original line shape parameters or experimental conditions under which the detection bandwidth has a negligible impact, given a targeted accuracy, are proposed. Particular emphasis is put on the detection bandwidth adjustments required to use such high-quality molecular spectra for a spectroscopic determination of the Boltzmann constant at the 1 ppm level of accuracy.

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Section: B Impact Of the Detection Bandwidth On Recorded Dipole Momementioning

confidence: 99%

Absorption-line-shape recovery beyond the detection-bandwidth limit: Application to the precision spectroscopic measurement of the Boltzmann constant

et al. 2014

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“…When such speed-dependent effects are considered, either the speed-dependent Voigt 35 (SDVP, Eq. (2)), speed-dependent Galatry (SDGP), 38 or speed-dependent Nelkin-Ghatak 39 (SDNGP, Eq. (3)) profiles are commonly used.…”

Section: Spectrum Analysismentioning

confidence: 99%

Observations of Dicke narrowing and speed dependence in air-broadened CO2 lineshapes near 2.06 μm

Bui

Long

Cygan

et al. 2014

The Journal of Chemical Physics

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The line shape problem in the near-infrared spectrum of self-colliding CO 2 molecules: Experimental investigation and test of semiclassical models J. Chem. Phys. 130, 184306 (2009) Frequency-stabilized cavity ring-down spectroscopy was used to study CO 2 lineshapes in the (20013) ← (00001) band centered near 2.06 μm. Two rovibrational transitions were chosen for this study to measure non-Voigt collisional effects for air-broadened lines over the pressure range of 7 kPa-28 kPa. Lineshape analysis for both lines revealed evidence of simultaneous Dicke (collisional) narrowing and speed-dependent effects that would introduce biases exceeding 2% in the retrieved air-broadening parameters if not incorporated in the modeling of CO 2 lineshapes. Additionally, correlations between velocity-and phase/state changing collisions greatly reduced the observed Dicke narrowing effect. As a result, it was concluded that the most appropriate line profile for modeling CO 2 lineshapes near 2.06 μm was the correlated speed-dependent NelkinGhatak profile, which includes all of the physical effects mentioned above and leads to a consistent set of line shape parameters that are linear with gas pressure. © 2014 AIP Publishing LLC.

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“…However, hard collision model is more difficult to apply in general situations as it explicitly assumes velocities after collision are unrelated to velocities before collisions [26]. Recently, more general line-fitting profiles taking into account velocity changes due to intermolecular collisions and speed dependence of collisional width have been developed for both soft collisional [27][28][29] and hard collisional models [30,31]. These speed dependent line profiles incorporate in-depth treatment of underlying physical phenomena and show better agreement with experimentally measured line profiles than soft and hard collisional models which do not account for speed dependence of broadening coefficients [32,33].…”

Section: Introductionmentioning

confidence: 99%

Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

Sajid

Es-sebbar

Farooq

2014

Journal of Quantitative Spectroscopy and Radiative Transfer

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Measurements of linestrengths, N2-, Ar-, He-and selfbroadening coefficients of acetylene in the 4+5 combination band using a cw quantum cascade laser KAUST Repository AbstractLinestrengths, N 2 -, Ar-, He-and self-broadening coefficients of acetylene have been measured at 296 K in the P branch of the ν 4 +ν 5 combination band for 25 rotational transitions. The effect of gas temperature is studied over 296 -683 K for five transitions to allow the determination of the temperature dependent exponent n for N 2 -and Ar-broadening coefficients. These measurements were performed using a continuous-wave quantum cascade laser (cw-QCL) operating over 1253 -1310 cm -1 . Spectroscopic parameters were obtained by fitting absorption spectra using Voigt, Galatry and Rautian profiles. Linestrength and broadening results are compared with previous studies available in literature for the ν 4 +ν 5 combination band and other vibrational bands of acetylene.

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Speed-dependent pressure broadening and shift in the soft collision approximation

Cited by 132 publications

References 24 publications

Absorption-line-shape recovery beyond the detection-bandwidth limit: Application to the precision spectroscopic measurement of the Boltzmann constant

Absorption-line-shape recovery beyond the detection-bandwidth limit: Application to the precision spectroscopic measurement of the Boltzmann constant

Observations of Dicke narrowing and speed dependence in air-broadened CO2 lineshapes near 2.06 μm

Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

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