Reactions in Omcvd: Detection of Gas Phase Radicals In Gaas Deposition Under Single Gas-Surface Collision Conditions

1987 ◽  
Vol 101 ◽  
Author(s):  
D.W. Squire ◽  
C.S. Dulcey ◽  
M.C. Lin
Keyword(s):  
Gas Phase ◽  
Ionization Mass ◽  
Laser Ionization ◽  
Methyl Radicals ◽  
Methyl Radical ◽  
Arrhenius Activation Energy ◽  
Gallium Atom ◽  
Surface Collision ◽  
Low Pressures ◽  
Radical Yield

ABSTRACTLaser ionization mass spectrometry has been used to study the deposition of gallium from trimethylgallium with and without AsH3. The apparent Arrhenius activation energy for the production of gas-phase methyl radicals from trimethylgallium is measured to be 28 ± 2 kcal/mol in the presence of AsH3, about the same value as measured in the absence of AsH3. At a substrate temperature of 1150 K where gallium desorption is substantial, addition of AsH3 is found to increase methyl radical yield but drastically decrease gallium atom desorption. A mechanism is presented to describe the deposition of GaAs at low pressures under single gas-surface collision conditions.

The Effect of Metal Atoms and Ligand Combinations in Organometallics on Excimer Laser Photoproducts and Yields

1988 ◽  
Vol 131 ◽  
Author(s):  
Y. Zhang ◽  
M. Stuke
Keyword(s):  
Mass Spectrometry ◽  
Laser Radiation ◽  
Gas Phase ◽  
Excimer Laser ◽  
Systematic Study ◽  
Ionization Mass ◽  
Laser Ionization ◽  
Metal Atoms ◽  
Excimer Laser Radiation

ABSTRACTA systematic study to find the role of different metal atoms and ligand combinations on the yield of the photoproducts generated upon irradiation of gas phase organometallics (i.e. metalalkyls) by uv excimer laser radiation was performed using laser ionization mass spectrometry.

scholarly journals Automated Analysis of Persistent Organic Pollutants in the Gas Phase by Laser Ionization Mass Spectrometry

2010 ◽  
Vol 58 (2) ◽  
pp. 35-46
Author(s):  
Shinsaku DOBASHI ◽  
Yoshiki YAMAGUCHI ◽  
Yoshinori IZAWA ◽  
Akihide WADA ◽  
Michikazu HARA
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Automated Analysis ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Laser Ionization

scholarly journals High-Pressure Gas Phase Femtosecond Laser Ionization Mass Spectrometry

2012 ◽  
Vol 84 (13) ◽  
pp. 5633-5640 ◽  
Author(s):  
Jiahui Peng ◽  
Noah Puskas ◽  
Paul B. Corkum ◽  
David M. Rayner ◽  
Alexandre V. Loboda
Keyword(s):  
Mass Spectrometry ◽  
High Pressure ◽  
Femtosecond Laser ◽  
Gas Phase ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Laser Ionization

Reaction of methyl radicals with cis-butene-2

1969 ◽  
Vol 47 (16) ◽  
pp. 2987-3001 ◽  
Author(s):  
Nobuo Yokoyama ◽  
R. K. Brinton
Keyword(s):  
Gas Phase ◽  
Equilibrium Distribution ◽  
Methyl Radicals ◽  
Methyl Radical ◽  
Hydrogen Atoms ◽  
Radical Concentration ◽  
Radical Decomposition ◽  
Similar Temperature ◽  
Carbonyl Radical

Methyl radicals generated by di-t-butylperoxide pyrolysis interact at comparable rates with cis-butene-2 in the gas phase by both addition and hydrogen atom abstraction. The determination of the rate of these reactions was simplified by the addition of a large concentration of acetaldehyde to the system. The additive, a source of low activation energy abstractable hydrogen atoms, was effective in suppressing polymerization reactions, and in addition, maintained a high steady state methyl radical concentration as a result of the carbonyl radical decomposition. The rate constants, k5 and k6 for the reactions [5] and [6], were determined to be 4.5 × 1010exp (−7000/RT)and 1.8 × 1010exp (−7300/RT)[Formula: see text]cm3 mole−1 s−1, respectively, over the temperature range 126–163 °C. The butenyl radical formed in reaction [6] isomerizes much faster than its interaction with other species in the system, and the distribution of the various conformations is similar to the equilibrium distribution of the butenes at a similar temperature.

The combustion of gaseous methyl iodide studied by flash photolysis and kinetic spectroscopy

1961 ◽  
Vol 263 (1312) ◽  
pp. 51-57 ◽  
Keyword(s):  
Free Radicals ◽  
Gas Phase ◽  
Methyl Iodide ◽  
Flash Photolysis ◽  
Oh Radicals ◽  
Methyl Radicals ◽  
Kinetic Spectroscopy ◽  
Slow Combustion ◽  
Low Pressures ◽  
Explosive Combustion

The combustion of gaseous methyl iodide has been studied under conditions of slow and explosive combustion and the behaviour of the methyl iodide, the free radicals OH and IO and the products formaldehyde and iodine has been followed by kinetic spectroscopy. At fairly low pressures ( l.0 to 5.5 cm Hg) the behaviour of the methyl iodide and the OH radicals under conditions of slow and explosive combustion indicates that the reaction between methyl radicals and oxygen proceeds by CH 3 + O 2 → H 2 CO + OH. At higher pressures, under slow combustion conditions, formaldehyde is detectable in the gas phase by reaction between methyl radicals and oxygen. Under slow combustion condi­tions also, the behaviour of the IO radicals and iodine suggests that the iodine atoms produced by the primary photolytic dissociation of m ethyl iodide are temporarily removed in the form of IO radicals, from which the final product iodine is then formed by 2IO → I 2 + O 2 .

MPI/MS Studies of Thin Film Deposition Processes: Methyl Production from Trimethylgallium Decomposition and the Effect of Added Hydrazine

1985 ◽  
Vol 54 ◽  
Author(s):  
D. W. Squire ◽  
C. S. Dulcey ◽  
M. C. Lin
Keyword(s):  
Thin Film ◽  
Gas Phase ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Radical Reactions ◽  
Ionization Mass ◽  
Methyl Radicals ◽  
Mass Analysis ◽  
Deposition Mechanism ◽  
Deposition Processes

ABSTRACTThe low pressure pyrolysis of alkylmetals on resistively heated substrates was studied using multiphoton and electron ionization mass analysis. The activation energy for the production of gas phase methyl radicals from the decomposition of trimethylgallium under single collision conditions was found to be 26 ± 3 kcal/mol, which is to be compared to 13 ± 2 kcal/mol previously observed for trimethylaluminum. No evidence could be found for any surface radical reactions leading to the production of CH4 or C2H6. A proposed deposition mechanism accounting for these observations was tested by pyrolyzing trimethylgallium in the presence of hydrazine. No change in methyl signal was observed, supporting the theory that radical reactions do not occur on the surface under the conditions employed.

Laser ionization mass analysis: its potential as a quantitative microanalytical technique

1986 ◽  
Vol 9 (1) ◽  
pp. 65-65 ◽  
Author(s):  
T. Dingle ◽  
B. W. Griffiths
Keyword(s):  
Ionization Mass ◽  
Laser Ionization ◽  
Mass Analysis ◽  
Microanalytical Technique
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