NH2 radical formation by ammonia pyrolysis in a temperature range of 800?1000�K

Rahinov, Igor; Ditzian, N.; Gol'dman, A. Ya.; Cheskis, Sergey

doi:10.1007/s00340-003-1267-7

Cited by 43 publications

(28 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The NH 3 consumption saturates relatively slow ͑for an NH 3 flow of ϳ7 sccs͒, which might indicate that a small amount of the NH 3 is dissociated by radicals produced by the initial NH 3 dissociation reactions. For completeness, we also mention that pyrolysis of NH 3 molecules due to the relatively high plasma temperatures can be neglected as this reaction has a rate constant below 1 ϫ 10 −18 cm 3 s −1 for a gas temperature of 1750 K. 48 For this gas temperature, also the dissociation of NH 3 by hydrogen atoms, which are produced by other NH 3 dissociation reactions, does not seem to play a significant role based on its relatively low reaction rate of ϳ4 ϫ 10 −12 cm 3 s −1 , 49 but this reaction will be reconsidered below.…”

Section: Fig 5 ͑A͒mentioning

confidence: 99%

Density and production of NH and NH2 in an Ar–NH3 expanding plasma jet

Oever

Helden

Lamers

et al. 2005

Journal of Applied Physics

View full text Add to dashboard Cite

The densities of NH and NH 2 radicals in an Ar-NH 3 plasma jet created by the expanding thermal plasma source were investigated for various source-operating conditions such as plasma current and NH 3 flow. The radicals were measured by cavity ringdown absorption spectroscopy using the ͑0,0͒ band of the A 3 ⌸ ← X 3 ⌺ − transition for NH and the ͑0,9,0͒-͑0,0,0͒ band of the Ã 2 A 1 ← X 2 B 1 transition for NH 2 . For NH, a kinetic gas temperature and rotational temperature of 1750± 100 and 1920± 100 K were found, respectively. The measurements revealed typical densities of 2.5 ϫ 10 12 cm −3 for the NH radical and 3.5ϫ 10 12 cm −3 for the NH 2 radical. From the combination of the data with ion density and NH 3 consumption measurements in the plasma as well as from a simple one-dimensional plug down model, the key production reactions for NH and NH 2 are discussed.

show abstract

Section: Fig 5 ͑A͒mentioning

confidence: 99%

Density and production of NH and NH2 in an Ar–NH3 expanding plasma jet

Oever

Helden

Lamers

et al. 2005

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The ammonia pyrolysis starts already at about 500 1C [5] and can be minimized using quartz (activation energy of 33.7 kcal/mol) for the reaction cell [6]. However, quartz limits the growth temperature, as SiO 2 gets reduced by the hydrogen arising from ammonia pyrolysis, which in turn results in Si-and O-donor doping of the grown material [7].…”

Section: Ammonia-based Vapour Growthmentioning

confidence: 99%

PVT growth of GaN bulk crystals

Siche

Gogova

Lehmann

et al. 2011

Journal of Crystal Growth

View full text Add to dashboard Cite

“…However, the hot lines start to appear in the spectrum already at 550 K, at which temperature the decomposition of NH 3 should be completely negligible. [48,49] Even at 820 K, the gas flows used in these experiments are high enough that the pyrolysis can be assumed to be negligible for the time the NH 3 gas spends in the heating tube.…”

Section: -4600 CM à1mentioning

confidence: 99%

Non‐intrusive, in situ detection of ammonia in hot gas flows with mid‐infrared degenerate four‐wave mixing at 2.3 µm

Sahlberg

Hot

Aldén

et al. 2016

J Raman Spectroscopy

View full text Add to dashboard Cite

We demonstrate non-intrusive, in situ detection of ammonia (NH 3 ) in reactive hot gas flows at atmospheric pressure using midinfrared degenerate four-wave mixing (IR-DFWM). IR-DFWM excitation scans were performed in the v 2 + v 3 and v 1 + v 2 vibrational bands of NH 3 around 2.3 μm for gas flow temperatures of 296, 550 and 820 K. Simulations based on spectroscopic parameters from the HITRAN database have been compared with the measurements in order to identify the spectral lines, and an absorption spectrum at 296 K has also been measured to compare with the IR-DFWM spectra. The signal-to-noise ratio of the IR-DFWM measurement was found to be higher than that of the absorption measurement. Some spectral lines in the measured IR-DFWM and absorption spectra had no matching lines in the HITRAN simulation. The detection limit of NH 3 diluted in N 2 with IR-DFWM in this spectral range was estimated at 296, 550 and 820 K to be 1.36, 4.87 and 7.06 × 10 16 molecules/cm 3 . The dependence of the NH 3 IR-DFWM signal on the quenching properties of the buffer gas flow was investigated by comparing the signals for gas flows of N 2 , Ar and CO 2 with small admixtures of NH 3 . It was found that the signal dependence on buffer gas was large at room temperature but decreased at elevated temperatures. These results show the potential of IR-DFWM for detection of NH 3 in combustion environments.

show abstract

NH2 radical formation by ammonia pyrolysis in a temperature range of 800?1000�K

Cited by 43 publications

References 16 publications

Density and production of NH and NH2 in an Ar–NH3 expanding plasma jet

Density and production of NH and NH2 in an Ar–NH3 expanding plasma jet

PVT growth of GaN bulk crystals

Non‐intrusive, in situ detection of ammonia in hot gas flows with mid‐infrared degenerate four‐wave mixing at 2.3 µm

Contact Info

Product

Resources

About