The self-consistent quantum-electrostatic problem in strongly non-linear regime

The self-consistent quantum-electrostatic (also known as Poisson-Schr\"odinger) problem is notoriously difficult in situations where the density of states varies rapidly with energy. At low temperatures, these fluctuations make the problem highly non-linear which renders iterative schemes deeply unstable. We present a stable algorithm that provides a solution to this problem with controlled accuracy. The technique is intrinsically convergent including in highly non-linear regimes. We illustrate our approach with (i) a calculation of the compressible and incompressible stripes in the integer quantum Hall regime and (ii) a calculation of the differential conductance of a quantum point contact geometry. Our technique provides a viable route for the predictive modeling of the transport properties of quantum nanoelectronics devices.Comment: 28 pages. 14 figures. Added solution to a potential failure mode of the algorith

A combined theoretical and experimental investigation on the influence of the bromine substitution pattern on the photophysics of conjugated organic chromophores

International audienceA large series of structurally related two-photon photosensitizers with heavy atom substitution were synthesized and evaluated through a combined spectroscopic (steady-state and time resolved), photophysical and computational study. Our aim was to identify some relevant parameters related to their excited state dynamics including photo-induced singlet oxygen generation. Although these dynamics result from the interplay of many factors, we show that the triplet excited state generation kinetics can generally be correlated with the calculated values of both the spin–orbit coupling and the energy gap between S1 and T1 states, which themselves mostly depend on the positioning of the heavy atoms along the π-conjugated structure rather than their number