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Chemical state
About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.
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01 Apr 1993-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this article, the surface chemical changes can be divided into three types, i.e., formation of a thin layer composed of the implanted atoms (B +, C + ), formation of new compounds between silicon and the bombarding ions (N +, O + ), and no chemical change (F +, Ne + ).
Abstract: Surface atomic composition and chemical state have been investigated for Si(100) bombarded with 5-keV ions of the second period elements in the periodic table. The XPS observations revealed that the surface chemical changes can be divided into three types, i.e., (1) formation of a thin layer composed of the implanted atoms (B + , C + ), (2) formation of new compounds between silicon and the bombarding ions (N + , O + ), and (3) no chemical change (F + , Ne + ). These changes are discussed in connection with irradiation-induced surface segregation of the implanted atoms and thermochemical stability of the Si compounds formed on the target surface.
2 citations
TL;DR: In this paper, a simple method of assessing the chemical consequences of mixing at interfaces between cool neutral gas with ionized material is proposed, and it is shown that the temperature within the interface has a significant effect; at low temperatures (∼ 10 K) the chemistry is significantly suppressed, but for temperatures above 100 K the chemistry initiated by proton/O-atom charge exchange gives rise to a rich and abundant chemistry.
Abstract: We propose a simple method of assessing the chemical consequences of mixing at interfaces between cool neutral gas with ionized material. It is shown that the temperature within the interface has a significant effect; at low temperatures (∼ 10 K) the chemistry is significantly suppressed, but for temperatures above 100 K the chemistry initiated by proton/O-atom charge exchange gives rise to a rich and abundant chemistry. The chemical state of the cool neutral gas has an important consequence for the interface. A mainly molecular cool gas can give rise to a high ionization state in the interface; this high ionization state appears stable against parameter variations. C2H is one of the most easily observed molecules having a high abundance in some interfaces.
2 citations
TL;DR: In this article, a series of pumice supported nickel catalysts used in the CO hydrogenation reaction were characterised by X-ray photoelectron spectroscopy, and the effect of the calcination conditions on the chemical state of the nickel before hydrogenation and the particle size of the metal after reduction.
Abstract: A series of pumice supported nickel catalysts used in the CO hydrogenation reaction were characterised by X-ray photoelectron spectroscopy. Qualitative and quantitative analysis of the XPS peaks have shown the effect of the calcination conditions on the chemical state of the nickel before hydrogenation and the particle size of the metal after reduction. Calcination at high temperature determined enrichment of sodium ions on the surface of the support and also on the metal particles. After exposure to the gas mixture CO/H2, formation of nickel carbides and other carbon species was checked. The correlation found between the surface atomic ratio Na/Si and the activity and selectivity of the catalysts in the hydrogenation of CO substantiated the role of the alkali ions naturally present in the pumice support.
2 citations
TL;DR: In this article, the chemical state, crystal structure and nano-indentation hardness of the modified layer were investigated and characterized with the use of X-ray photo-electron spectroscopy (XPS), XRD and a nanoindentor, which indicated that after the injection of Sn ions into the W matrix, Sn atoms interacted intensively with W, leading to the generation of a large number of point defects (such as vacancies and self-interstitial atoms) and the decrease of average grain size from 16.7 to 11.9
2 citations
TL;DR: In this article, aluminum nitride and oxy-nitride thin films have been deposited on Si(100) substrates at temperatures of 300-350K by gas-phase excimer laser photolysis at 193 nm.
Abstract: Aluminum nitride and oxy-nitride thin films have been deposited on Si(100) substrates at temperatures of 300-350K by gas-phase excimer laser photolysis at 193 nm. The precursors used for this deposition process are trimethylamine alane and ammonia. The properties of these laser-deposited films were studied using scanning electron microscopy, energy dispersive x-ray analysis, and x-ray diffraction. X-ray photoelectron spectroscopy has been extensively used to provide information regarding the chemical compositions on the surface and in the bulk of these laser deposited films, as well as on the chemical states of the components of the films. Well-adhering, smooth, amorphous films of AlN are obtained at a substrate temperature of 350K using this technique.
2 citations