Many electron atoms, under plasma

Earlier calculation on many electron atomic systems under plasma was performed by Stewart and Pyatt [58], who estimated the variation of IP of several atoms using a finite temperature TF model. Applications of the density functional theory on these systems were reviewed by Gupta and Rajagopal [57], The calculations on many electron systems are mostly concerned with the hot and dense plasmas with the application of the IS model, or from general solutions of the Poisson equation for the potential function. The discussions using the average atom model in Section 3.3, Inferno model of Liberman in 3.4, STA model in 3.5, hydrodynamic model in... 

Investigations on the doubly excited states of two electron systems under weakly coupled plasma have been performed by several authors. Such states usually occur as resonance states in electron atom collisions and are usually autoionizing [225]. Many of these states appear in solar flare and corona [226,227] and contribute significantly to the excitation cross-sections required to determine the rate coefficients for transitions between ionic states in a high temperature plasma. These are particularly important for dielectronic recombination processes which occur in low density high temperature plasma, occurring e.g. in solar corona. Coronal equilibrium is usually guided by the balance between the rates of different ionization and... 

We may compare results presented here with those obtained in two types of inductively coupled reactors [, 3]. One is the reactor we have used for many years [4], in which the portion of the reactor inserted into the r.f. coil is smaller than the main portion of the reactor, in which plasma polymer is collected. Monomer flux is directed into the main portion of the reactor, not through the r.f. coil. Electron bombardment of plasma polymer and substrate is reduced in this way [ ]. Active species are formed mainly under the r.f. coll and are transported by diffusion to the entire volume of the reactor. Interaction of these non-polymerizable energy carrying species (e.g. electrons, excited atoms) with the monomer entering the reactor leads to plasma polymerization [ ]. 

Many attempts have been made to quantify SIMS data by using theoretical models of the ionization process. One of the early ones was the local thermal equilibrium model of Andersen and Hinthome [36-38] mentioned in the Introduction. The hypothesis for this model states that the majority of sputtered ions, atoms, molecules, and electrons are in thermal equilibrium with each other and that these equilibrium concentrations can be calculated by using the proper Saha equations. Andersen and Hinthome developed a computer model, C ARISMA, to quantify SIMS data, using these assumptions and the Saha-Eggert ionization equation [39-41]. They reported results within 10% error for most elements with the use of oxygen bombardment on mineralogical samples. Some elements such as zirconium, niobium, and molybdenum, however, were underestimated by factors of 2 to 6. With two internal standards, CARISMA calculated a plasma temperature and electron density to be used in the ionization equation. For similar matrices, temperature and pressure could be entered and the ion intensities quantified without standards. Subsequent research has shown that the temperature and electron densities derived by this method were not realistic and the establishment of a true thermal equilibrium is unlikely under SIMS ion bombardment. With too many failures in other matrices, the method has fallen into disuse. 

The difference between conventional and magnetron processes lies largely in the plasma environment. As will be shown later, the plasma is confined to the surface of the cathode by a magnetic field created by permanent magnets located under the target and by an electric field which is situated perpendicularly to the surface. The electrons travel in spiral trajectories and can thus carry out many ionizing collisions with the atoms of the sputter gas. Either the whole vacuum chamber is used as anode or the anode is built of metal or metal bars, which are positioned near to the chath-ode. 

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