Complete experimental sampling of potential energy surfaces of small polyatomic molecules

This research field is based on the idea that it is possible to connect quantum chemistry and physics trough eigenstate resolved molecular spectroscopy. To obtain relevant to chemistry experimental results it is important to sample not only the rotational manifold of the fundamental normal modes of the molecule, but we also need to do spectroscopy of the highly excited molecular states which are relevant to chemical reactions. Moreover this experimental method allows to sample the complete discrete eigenenergy spectrum of the molecules allowing a complete physical representation of the potential energy surface, the basic concept of quantum chemistry. My [H,C,N] hot gas spectroscopic experiments allowed for the first time to give a full eigenstate resolved characterization of a polyatomic molecule up to excitation energies typical for chemical reactions. This data set allows to answer some very basic questions of quantum chemistry: the overall accuracy of the BO approximation, the scientific role of the global potential surfaces determined by fitting the PES to experimental data (procedure needed to improve the accuracy of the predicted eigenenergies below 1 cm^-1), the test of the different analytic representations of the global potential energy surface etc.
One very important research project I intend to continue in the next years is the extension of the [H,C,N] complete data set to higher energies and set up similar data sets for CO₂ and H₂O.