Multi-pressure analysis of the ν4 and 2ν2 bands of ammonia: self-broadening, self-mixing, and pressure-induced self-shifts

Mabrouk, K. Ben; Galalou, S.; Aroui, H.; Orphal, J.

doi:10.1080/00268976.2010.498388

Cited by 6 publications

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“…Accurate knowledge of the NH 3 spectrum -especially the strong 2 band in the 10 µm region -as well as lineshape parameters are in particular indispensable to enable astrophysical and planetary interpretations. Several accurate laboratory studies have been performed, using high resolution Fourier transform or tunable laser diode spectrometers, to provide lineshape parameters for the 2 band [10][11][12][13][14][15][16][17][18]. Absolute frequencies, intensities, self-broadening and self-shift coefficients have been recently re-measured in the R branch of the 2 band by Guinet et al [19].…”

Section: Introductionmentioning

confidence: 99%

Speed-dependent effects in NH3self-broadened spectra: Towards the determination of the Boltzmann constant

et al. 2012

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In this paper we present an accurate analysis of the shape of an isolated rovibrational ammonia line from the strong 2 band around 10 µm, recorded by laser absorption spectroscopy. Experimental spectra obtained under controlled temperature and pressure, are confronted to various models that take into account Dicke narrowing or speed-dependent effects. Our results show clear evidence for speed-dependent broadening and shifting, which had never been demonstrated so far in NH 3 . Accurate lineshape parameters of the ν 2 saQ(6,3) line are obtained. Our current project aiming at measuring the Boltzmann constant, k B , by laser spectroscopy will straight away benefit from such knowledge. We anticipate that a first optical determination of k B with a competitive uncertainty of a few ppm is now reachable.

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