Coulomb Explosion Imaging studies of fundamental molecular structure

Abstract

Foil-induced Coulomb explosion imaging is an accurate technique to measure bondlength distributions and geometries of molecules. Two fundamental questions are addressed in this thesis concerning metastable states of the diatomic hydrogen anions H2- and D2- and the more complex radical cation C2OH2D2+ of trans-2,3-dideuterooxirane. The measurements on the rotationally stretched and metastable D2- were preformed to investigate a discrepancy between a nonlocal resonance theory and a previous photofragmentation study. An agreement is found with theory for the calculated wave functions of states with rotational quantum numbers of J = 37 and J = 38 and also the photofragmentation data agree with theory when considering a so far neglected fragmentation channel. The study of the trans-2,3-dideuterooxirane represents the first determination of molecular handedness from an enantiopure sample by direct molecular imaging and reached a statistical significance of 5s. The structures of chiral molecules are related to different chemical properties, while except for the optical activity their physical properties are the same. The applied enantiopure deuterated oxirane sample was chemically linked to the stereochemical reference standard, realizing the first gas-phase test of the fundamental relation between chemical properties and chiral structure that was arbitrarily chosen by Fischer in 1894.