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Title: Density and production of NH and NH{sub 2} in an Ar-NH{sub 3} expanding plasma jet

Abstract

The densities of NH and NH{sub 2} radicals in an Ar-NH{sub 3} plasma jet created by the expanding thermal plasma source were investigated for various source-operating conditions such as plasma current and NH{sub 3} flow. The radicals were measured by cavity ringdown absorption spectroscopy using the (0,0) band of the A {sup 3}{pi}<-X {sup 3}{sigma}{sup -} transition for NH and the (0,9,0)-(0,0,0) band of the A-tilde{sup 2}A{sub 1}<-X-tilde{sup 2}B{sub 1} transition for NH{sub 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 2.5x10{sup 12} cm{sup -3} for the NH radical and 3.5x10{sup 12} cm{sup -3} for the NH{sub 2} radical. From the combination of the data with ion density and NH{sub 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{sub 2} are discussed.

Authors:
; ; ; ; ; ;  [1]
  1. Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
Publication Date:
OSTI Identifier:
20719649
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 98; Journal Issue: 9; Other Information: DOI: 10.1063/1.2123371; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION SPECTROSCOPY; AMMONIA; ARGON; DISSOCIATION; ION DENSITY; ONE-DIMENSIONAL CALCULATIONS; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA JETS; RADICALS

Citation Formats

Oever, P.J. van den, Helden, J.H. van, Lamers, C.C.H., Engeln, R., Schram, D.C., Sanden, M.C.M. van de, and Kessels, W.M.M. Density and production of NH and NH{sub 2} in an Ar-NH{sub 3} expanding plasma jet. United States: N. p., 2005. Web. doi:10.1063/1.2123371.
Oever, P.J. van den, Helden, J.H. van, Lamers, C.C.H., Engeln, R., Schram, D.C., Sanden, M.C.M. van de, & Kessels, W.M.M. Density and production of NH and NH{sub 2} in an Ar-NH{sub 3} expanding plasma jet. United States. doi:10.1063/1.2123371.
Oever, P.J. van den, Helden, J.H. van, Lamers, C.C.H., Engeln, R., Schram, D.C., Sanden, M.C.M. van de, and Kessels, W.M.M. Tue . "Density and production of NH and NH{sub 2} in an Ar-NH{sub 3} expanding plasma jet". United States. doi:10.1063/1.2123371.
@article{osti_20719649,
title = {Density and production of NH and NH{sub 2} in an Ar-NH{sub 3} expanding plasma jet},
author = {Oever, P.J. van den and Helden, J.H. van and Lamers, C.C.H. and Engeln, R. and Schram, D.C. and Sanden, M.C.M. van de and Kessels, W.M.M.},
abstractNote = {The densities of NH and NH{sub 2} radicals in an Ar-NH{sub 3} plasma jet created by the expanding thermal plasma source were investigated for various source-operating conditions such as plasma current and NH{sub 3} flow. The radicals were measured by cavity ringdown absorption spectroscopy using the (0,0) band of the A {sup 3}{pi}<-X {sup 3}{sigma}{sup -} transition for NH and the (0,9,0)-(0,0,0) band of the A-tilde{sup 2}A{sub 1}<-X-tilde{sup 2}B{sub 1} transition for NH{sub 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 2.5x10{sup 12} cm{sup -3} for the NH radical and 3.5x10{sup 12} cm{sup -3} for the NH{sub 2} radical. From the combination of the data with ion density and NH{sub 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{sub 2} are discussed.},
doi = {10.1063/1.2123371},
journal = {Journal of Applied Physics},
number = 9,
volume = 98,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}
  • The densities of N, NH, and NH{sub 2} radicals in a remote Ar-NH{sub 3}-SiH{sub 4} plasma used for high-rate silicon nitride deposition were investigated for different gas mixtures and plasma settings using cavity ringdown absorption spectroscopy and threshold ionization mass spectrometry. For typical deposition conditions, the N, NH, and NH{sub 2} radical densities are on the order of 10{sup 12} cm{sup -3} and the trends with NH{sub 3} flow, SiH{sub 4} flow, and plasma source current are reported. We present a feasible reaction pathway for the production and loss of the NH{sub x} radicals that is consistent with the experimentalmore » results. Furthermore, mass spectrometry revealed that the consumption of NH{sub 3} was typically 40%, while it was over 80% for SiH{sub 4}. On the basis of the measured N densities we deduced the recombination and sticking coefficient for N radicals on a silicon nitride film. Using this sticking coefficient and reported surface reaction probabilities of NH and NH{sub 2} radicals, we conclude that N and NH{sub 2} radicals are mainly responsible for the N incorporation in the silicon nitride film, while Si atoms are most likely brought to the surface in the form of SiH{sub x} radicals.« less
  • Reaction of LaCl{sub 3} with 3 equiv of sodium metal in liquid ammonia at -78 {degrees}C, followed by addition of 3 equiv of HOAr (Ar = 2,6-i-Pr{sub 2}C{sub 6}H{sub 3}) in toluene produces La(OAr){sub 3}(NH{sub 3}){sub x} (1) after warming to room temperature. Dissolution of 1 in toluene followed by 6 h reflux provides La{sub 2}(OAr){sub 6} (2) in good yield. An X-ray crystallographic study revealed that 2 contains a dimeric unit held together with two {eta}{sup 6}-arene bridges formed from aryloxide ligands with La-C(av) = 3.062(10) {Angstrom}. The La-O distances average 2.193(5) and 2.273(5) {Angstrom} for terminal and bridgingmore » aryloxide ligands, respectively. Dissolution of 1 in toluene followed by vacuum filtration and crystallization from toluene without reflux yields La{sub 2}(OAr){sub 6}(NH{sub 3}){sub 2}(3) in high yield. The X-ray crystal structure of 3 reveals an alternate dimeric structure bridged by oxygen atoms of the aryloxide ligands. X-ray crystallography has shown that a third compound may be isolated by gravity filtration and crystallization of 1 to produce La(OAr){sub 3}(NH{sub 3}){sub 4} (4). 4 displays a capped pseudo-octahedral geometry around the metal center with facial aryloxide ligands average 2.252(6) {Angstrom}. The La-N distances for the NH{sub 3} ligands average 2.750(9) {Angstrom} with no significant lengthening of the capped La-N bond.« less
  • Inspired by the Penning effect, we obtain a glow-like plasma jet by mixing ammonia (NH{sub 3}) into argon (Ar) gas under atmospheric pressure. The basic electrical and optical properties of an atmospheric pressure plasma jet (APPJ) are investigated. It can be seen that the discharge mode transforms from filamentary to glow-like when a little ammonia is added into the pure argon. The electrical and optical analyses contribute to the explanation of this phenomenon. The discharge mode, power, and current density are analyzed to understand the electrical behavior of the APPJ. Meanwhile, the discharge images, APPJ's length, and the components ofmore » plasma are also obtained to express its optical characteristics. Finally, we diagnose several parameters, such as gas temperature, electron temperature, and density, as well as the density number of metastable argon atoms of Ar/NH{sub 3} APPJ to help judge the usability in its applications.« less
  • Trace amounts of H/sub 2/O and limited exposure to air of reaction mixtures of UCl/sub 4/ and 12-crown-4, 15-crown-5, benzo-15-crown-5, 18-crown-6, or dibenzo-18-crown-6 in 1:3 mixtures of CH/sub 3/OH and CH/sub 3/CN resulted in the hydrolysis and oxidation of UCl/sub 4/ to (UO/sub 2/Cl/sub 4/)/sup 2/minus//. In the presence of these crown ethers, it has been possible to isolate intermediate products via crystallization of crown complexes of the (UO/sub 2/Cl/sub 4/)/sup 2/minus// ion, the (UCl/sub 6/)/sup 2/minus// ion, and (UO/sub 2/Cl/sub 2/(OH/sub 2/)/sub 3/). The neutral moiety crystallizes as a hydrogen-bonded crown ether complex; however, crown ether complexation of amore » counterion, either an ammonium ion formed during the oxidation of U(IV) or a Na/sup +/ ion leached from glass reaction vessels, resulted in novel crystalline complexes of the ionic species. ((NH/sub 4/)(15-crown-5)/sub 2/)/sub 2/(UO/sub 2/Cl/sub 4/) /times/ 2CH/sub 3/CN, ((NH/sub 4/)(benzo-15-crown-5)/sub 2/)/sub 2/(UCl/sub 6/) /times/ 4CH/sub 3/CN, and ((NH/sub 4/)(dibenzo-18-crown-6))/sub 2/(UO/sub 2/Cl/sub 4/) /times/ 2CH/sub 3/CN have been structurally characterized by single-crystal X-ray diffraction techniques. The results of all the crystal studies are presented in detail. The ammonium ions interact with the crown ethers via hydrogen-bonding and electrostatic interactions. 15-Crown-5 and benzo-15-crown-5 form 2:1 sandwich cations, allowing no H/sub 4/N/sup +//hor ellipsis/(UO/sub 2/Cl/sub 4/)/sup 2/minus// interaction. The dibenzo-18-crown-6 complexed ammonium ions are 1:1 and form bifurcated hydrogen bonds with the chlorine atoms in the (UO/sub 2/Cl/sub 4/)/sup /minus// anion. The formation of (Na(12-crown-4)/sub 2//sub 2/(UO/sub 2/Cl/sub 4/) /times/ 2OHMe and (UO/sub 2/Cl/sub 2/(OH)/sub 2/)/sub 3/) /times/ 18-crown-6 /times/ H/sub 2/O /times/ OHMe has been confirmed by preliminary single-crystal X-ray diffraction studies.« less
  • Single crystals of (NH{sub 3}(CH{sub 2}){sub 3}NH{sub 3})(H{sub 3}O){sub 2}(UO{sub 2}){sub 3}(MoO{sub 4}){sub 5} (1), C(NH{sub 2}){sub 3}(UO{sub 2})(OH)(MoO{sub 4}) (2), (C{sub 4}H{sub 12}N{sub 2})(UO{sub 2})(MoO{sub 4}){sub 2} (3) and (C{sub 5}H{sub 14}N{sub 2})(UO{sub 2})(MoO{sub 4}){sub 2}{center_dot}H{sub 2}O (4) have been synthesized hydrothermally by using UO{sub 2}(CH{sub 3}COO){sub 2}{center_dot}2H{sub 2}O, (NH{sub 4}){sub 2}Mo{sub 2}O{sub 7}, HF{sub (aq)}, H{sub 2}O, and the respective organic template. The materials have layered structures with anionic uranium molybdate sheets separated by cationic organic templates. Compound 1 has an unprecedented uranium molybdate topology, whereas 2 is structurally related to johannite, Cu[(UO{sub 2}){sub 2}(SO{sub 4}){sub 2}(OH){sub 2}](H{submore » 2}O){sub 8}, and 3 and f4 have layer topologies similar to zippiete, K{sub 2}[UO{sub 2}(MoO{sub 4}){sub 2}]. Thermogravimetric measurements indicate all that four materials, after template loss, form a crystalline mixture of UO{sub 2}MoO{sub 4} and MoO{sub 3}. Crystal data: (NH{sub 3}(CH{sub 2}){sub 3}(H{sub 3}O){sub 2}(UO{sub 2}){sub 3}(MoO{sub 4}){sub 5}, orthorhombic, space group Pbnm (No. 62), with a = 10.465(1) {angstrom}, b = 16.395(1) {angstrom}, c = 20.241(1) {angstrom}, and Z = 4; C(NH{sub 2}){sub 3}(UO{sub 2})(OH)MoO{sub 4}), monoclinic, space group P2{sub 1}/c (No. 14), with a = 15.411(1) {angstrom}, b = 7.086(1) {angstrom}, c = 18.108(1) {angstrom}, {beta} = 113.125(2){degree}, and Z = 4; (C{sub 4}H{sub 12}N{sub 2})(UO{sub 2})(MoO{sub 4}){sub 2}, triclinic, space group P{bar 1} (No. 2), with a = 7.096(1) {angstrom}, b = 8.388(1) {angstrom}, c = 11.634(1) {angstrom}, {alpha} = 97.008(3){degree}, {beta} = 96.454(2){degree}, {gamma} = 110.456(3){degree}, and Z = 2; (C{sub 5}H{sub 14}N{sub 2})(UO{sub 2})(MoO{sub 4}){sub 2}{center_dot}H{sub 2}O, orthorhombic, space group Pbca (No. 61), with a = 12.697(1) {angstrom}, b = 13.247(1) {angstrom}, c = 17.793(1) {angstrom}, and Z = 8.« less