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In-situ small- and wide-angle scattering experiments at synchrotrons often result in massive amounts of data within seconds only. Especially during such beamtimes, processing of the acquired data online, so without mentionable delay, is key to obtain feedback on failure or success of the experiment. We thus developed SAXSDOG, a python based environment for real-time azimuthal integration of large-area scattering-images. The software is primarily designed for dedicated data-pipelines: once a scattering image is transferred from the detector onto the storage-unit, it is automatically integrated and pre-evaluated using integral parameters within milliseconds. The control and configuration of the underlying server-based processes is done via a graphical user interface SAXSLEASH, which visualizes the resulting 1D data together with integral classifiers in real time. SAXSDOG further includes a portable 'take-home' version for users that runs on standalone computers, enabling its use in labs or at the preferred workspace., Comment: Source-code available at https://github.com/maxburian/SAXS_py3

The solution of the Bethe-Salpeter equation within the framework of many-body perturbation theory has turned out to be a benchmark for ab-initio calculations of optical properties of semiconductors and insulators. Commonly, however, the coupling between the resonant and anti-resonant excitations is neglected which is referred to as the Tamm-Dancoff approximation (TDA). This is well justified in cases where the exciton binding energy is much smaller than the band gap. Here, we report on the optical properties of a representative series of organic semiconductors where we find the TDA to no longer hold. We observe an increase of the exciton binding energy of up to 44% thereby improving the agreement with experiment.