Nuclear Dynamics of Core-Excited and Ionized Small Polyatomic Molecules Probed by Multiple Coincidence Momentum Imaging Technique

Abstract

Our recent studies on nuclear dynamics of core-excited and core-ionized molecules probed by a multiple coincidence momentum imaging technique are reviewed. This technique consists of a time-of-flight spectrometer with a multi-hit two-dimensional position sensitive detector and a supersonic jet. One can probe the symmetries and the nuclear motions of polyatomic molecules using this technique. As a specific example, we illustrate how to resolve the symmetries of the CO2 C 1s−12πu core-excited states, which split into two states, A1 and B1, due to D∞h → C2v symmetry lowering by the static Renner-Teller effect, and how to probe the nuclear motion caused in these states. We discuss also symmetry lowering D3h → C3v and D3h → C2v initiated by the B 1s → 4a2'' excitation and F 1s ionization, respectively, in the BF3 molecule and nuclear motions in these core-excited and ionized states.