Chemistry, Light and Dynamics Group Seminar

In this seminar I will describe some tools developed over the last few years to model non-linear spectroscopies with parameters extracted from first principles, particularly when applying multireference perturbation theory (CASPT2). I will discuss the main magnitudes required, how these might be benchmarked across different electronic structure theory methods, and how they might be applied in different ways to simulate both 1D and 2D non-linear optical spectra. Models with different levels of approximation will be shown, looking at the trade-off between cost and accuracy, and identifying those cases where an accurate description of complex aspects like spectral line shapes are mandatory. I will discuss different ways to include solvent, conformation effects and the temporal evolution of the signals, and how this affects both 1D and 2D spectra. The main goal is to show connections between computed and measured spectra, and to provide simple tools that allow assigning and sometimes even predicting non-linear signals, helping bridge the gap between theory and experiment.