FWF - ELFIS - Electronic fingerprint spectroscopy

Our knowledge about how a molecule maneuvers through the complex potential landscape while undergoing a reaction is largely derived from optical absorption measurements. Different reactants and even individual molecules in different configurations absorb light of characteristic frequencies which is used as a fingerprint of their participation in a chemical process. Conceptually, a chemical reaction is driven by charge relocation between the electronic states of a molecule which is followed by the rearrangement of the nuclei. As a concession to the light sources available to date, spectroscopic fingerprinting is almost exclusively done in the narrow frequency band between visible and mid-infrared frequencies and thus tracks only the rotational and vibrational kinetics of molecular species. The project Electronic Fingerprint Spectroscopy (ELFIS) adapts one of the most powerful modern concepts of ultra-precision laser fingerprinting – dual frequency comb Fourier transform spectroscopy – to the visible-to-ultraviolet frequency range relevant to sample electronic transitions, too. This expands the frequency-band for element-specific molecular tracking by several octaves and promises more accurate spectroscopic data, orders of magnitude higher sensitivity and record short acquisition times that we will first exploit to investigate atmospheric and astrophysical photochemistry at an unprecedented level of detail. Solar ultraviolet driven atmospheric photochemistry strongly influences life on earth. ELFIS with its unparalleled spectro-temporal resolving power will identify the reaction pathways of environmental trace gas reactions and explore transient electronic states that propel photo-induced molecular dynamics, photolysis and aerosol nucleation essential to live beyond the reach of current experiments. We envisage this next-level spectroscopy platform to become a prime tool for the kinematically complete and fully state resolved exploration of virtually all photo-induced processes. That includes biological and technological light-to-energy conversion, catalytic atmospheric reactions and the photochemistry of sight.