Atomic substrate-molecule-particle

In secondary-ion mass spectrometery (SIMS) and its sister technique fast atom bombardment mass spectrometry (FARMS), a surface is bombarded with energetic particles, and the kinetic energy of the particles converts substrate and chemisorbed atoms and molecules to gas-phase species. The ejected (or sputtered) material is subsequently interrogated using various analytical tools, such as lasers and mass spectrometers, to indirectly deduce information about the initial surface. The relationships between sputtered material and the surface, however, are not always clear, and erroneous conclusions are easily made. Computer simulations have demonstrated that a fundamental understanding of the sputtering process is required to interpret experimental data fully ... 

There is something positively bizarre about the modern, reductionist denial of persons. To be sure, brains in craniums exist and so do persons in societies. The material substrates of human beings or persons are, indeed, organs, tissues, cells, molecules, atoms, and subatomic particles. And so, too, are the material substrates of human artifacts, say a wedding ring. Scientists do not claim... 

The industrial development of these evaporation and condensation techniques is due largely to the relative ease of obtaining either pure metal films or exact stoichiometric compound deposits of uniform thickness, because the laws which determine the phenomena at low pressure are better defined than close to or at atmospheric pressure. At very low pressures, the mean free path of the vapour atoms or molecules exceeds the usual distance between evaporation source and (he substrate. Thus the substrate receives a flux of vapour particles which travel in straight lines with only very few gas/vapour collisions and the spatial distribution of the condensate obeys purely geometrical laws. 

A portion of these atoms and molecules is adsorbed on the substrate surfaces, and another portion is either reflected or, after a short dwell on the surface, again desorbed. The ratio of the actually adsorbed quantity to the number of incident particles is given by the condensation coefficient ct. 

There are two processes responsible for the fact that a portion of the incident atoms and molecules leave the surface again. An incident particle can rebound immediately if its translational energy is not absorbed by the substrate upon incidence. Fast desorption takes place if either a very small adsorption energy exists or the substrate has a high temperature. 

In ion-plating deposition, the substrate and the deposited film (as it forms) are subj ected to bombardment by particles (ions, atoms, molecules) which alter the formation process and the properties of the coating.The process is also calltd ion-beam assisted deposition (TOAD). 

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