Projets soutenus

The collaboration between the LSI and the CRC (co-partner in the ENIGME project) has shown very promising results. The goal of the collaboration (funded, via the ENIGME project, by the DIM Matériaux Anciens et Patrimoniaux) is to tackle both via experimental techniques and via numerical simulation, the description and understanding of the first color photography of history, made by Edmond Becquerel in 1848. This photography still poses a great theoretical challenge, because the photochromatic procedure has not been explained yet. The crucial importance of the numerical analysis (and of the predictive power of the ab initio simulation) is underlined by the fact that the original clichés by Becquerel cannot be exposed (they are not fixed), let alone analyzed by any form of irradiation. The preliminary results of the theory, conducted at the LSI are validated by measurements conducted by the CRC, in a joint experimental session at the electron microscope of the LPS, in Orsay. The results of the collaboration point definitely towards nano-structural reasons for the absorption of light in silver chloride based materials. This new direction of the project implies the analysis and the prediction of both: i) new effects in the description of the light-matter interaction as it happens in this kind of systems (for example, by exploring the possibility of self-trapped excitons); ii) new nanostructures based on silver chloride made by tens or even hundreds of atoms. Both these directions will require an increased computational power to be efficiently tackled, which justifies our request for an equipment dedicated to the ENIGME project.