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Vizia, Maria Domenica De; Rohart, F.; Castrillo, A.; Fasci, Eugenio; Moretti, Luigi; Gianfrani, L.

doi:10.1103/physreva.83.052506

Cited by 59 publications

(44 citation statements)

References 30 publications

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“…This finding is consistent with previous observations by Long et al 11 for CO 2 lines near 1.6 μm as well as for other systems. 16,19,57,59,61,62 As shown in Fig. 2, the single-spectrum fit analysis with the SDNGP can reproduce the investigated spectra down to the instrument noise level.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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 required technical improvements and upgrades of the spectrometers have been accompanied by an increasingly refined interpolation of the experimental profiles [44][45][46][47]. Particularly, a great attention is being paid to the role of speed-dependent effects [39,48]. Also, other molecules and atoms such as Rb, H 2 18 O or C 2 H 2 are now probed [32,49,50].…”

Section: Doppler Broadening Thermometrymentioning

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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“…Other groups followed our initiative in measuring k B using the DBT, but probing other species such as CO 2 , H 2 O, C 2 H 2 and Rb [43,[52][53][54][55]. Table 1 gives the corresponding state-of-art for the statistical uncertainty obtained on k B .…”

Section: Statistical Uncertaintymentioning

confidence: 99%

“…It for instance, constituted 97% of the 144 ppm standard uncertainty published in [29]. The influence of the lineshape model on the spectroscopic determination of the Boltzmann constant has been raised by us and other groups working with O 2 and H 2 O [29,32,[40][41][42][43][44][45]. We recently carried out an extensive lineshape study at relatively high pressure in SPC, in order to enhance collisional effects and to determine the most suitable model for our data [40].…”

Section: The Lineshape Problemmentioning

confidence: 99%

Accurate determination of the Boltzmann constant by Doppler spectroscopy: Towards a new definition of the kelvin

Darquié

Mejri

Sow

et al. 2013

EPJ Web of Conferences

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Abstract. Accurate molecular spectroscopy in the mid-infrared region allows precision measurements of fundamental constants. For instance, measuring the linewidth of an isolated Doppler-broadened absorption line of ammonia around 10 m enables a determination of the Boltzmann constant k B . We report on our latest measurements. By fitting this lineshape to several models which include Dicke narrowing or speeddependent collisional effects, we find that a determination of k B with an uncertainty of a few ppm is reachable. This is comparable to the best current uncertainty obtained using acoustic methods and would make a significant contribution to any new value of k B determined by the CODATA. Furthermore, having multiple independent measurements at these accuracies opens the possibility of defining the kelvin by fixing k B , an exciting prospect considering the upcoming redefinition of the International System of Units.

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Speed-dependent effects in the near-infrared spectrum of self-collidingH2O18m

Cited by 59 publications

References 30 publications

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

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

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

Accurate determination of the Boltzmann constant by Doppler spectroscopy: Towards a new definition of the kelvin

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