Using a deposited Al layer, optical processing at a temperature below the Si-Al eutectic temperature of T eu =577 o C for a few minutes and followed by T>T eu for a few more minutes are able to getter metallic precipitates out of multicrystalline Si. To accomplish the same, a few tens of hrs is needed when using thermal annealing at 700 o C. Possible mechanisms involved in opticalprocessing gettering are proposed. These mechanisms include vacancy injection, radiationenhanced solubility, and radiation-enhanced diffusion of vacancies and metal impurity atoms. Using FeSi 2 as a model case for which the Si lattice expands concomitantly with the dissolution of the precipitates, physical modeling and numerical simulations are carried out to uncover and test the conditions for the mechanisms to be effective. The mechanisms are found to be effective provided that the injected Si vacancies due to alloy formation are nearly all retained inside and evenly distributed throughout the Si bulk at the lower temperature, and that the Fe atom migration energy barrier is reduced by ~0.15 eV by radiation at the higher temperature. On the other hand, for the gettering of a precipitate species for which the Si lattice will shrink concomitantly with the dissolution of the precipitates, the vacancy-injection mechanism will not only be ineffective but should also have a detrimental effect.

STRUCTURE/PROPERTY RELATIONSHIPS gy (J < 0). This behaviour opposes entirely to the one of Dioxin possessing a combination of four n: electron Spins with a singlet ground state (S=O) and a positive exchange energy (J > 0). Special binding complexes of Dioxin to XD* structures have been also observed with a negative exchange energy (J < 0). These [XD*-Dioxin] complexes appear with a very high probability, about 105 times of the one ofthe [Hemoglobin-Dioxin] complex in hnman blood and of the [Mn-Porphy1inoprotein-Dioxin] complex in human liver. The properties of these interaction complexes conesponding with the results achieved in some respective expelimental clinical studies over a long peliod of time suggest that the specific natural XD* structures are able to conquer and arrest potently Dioxin molecules, i.e. to interact concurently contrary to the toxicity of Dioxin, namely to its carcinogenous activity. This activity depends on many factors such as the concentration and the lifetime of the XD* state, the kinetic conditions of the surrounding and the interaction.