Anion photoelectron spectroscopic and reactivity studies of gas phase biomolecules, diffusely bound electron states, aluminum clusters, and rare earth doped silicon clusters

Here photoelectron spectroscopic and reactivity studies were done on gas phase, anionic, molecules and clusters. The photoelectron studies were carried out here in the Bowen lab at Johns Hopkins University using both our continuous and pulsed photoelectron spectrometers. The reactivity studies were done in Karlsruhe, Germany in the lab of Prof Hansgeorg Schnockel using the FT-ICR mass spectrometer available there.; The study of biological molecules is of interest mostly because of a desire to gain a molecular level understanding of problems in radiation biology. Additionally, learning about the intrinsic properties of biomolecules minus the interfering effects of surrounding solvent molecules is a goal. To these ends, photoelectron studies were carried out on nucleosides and nucleotides and thereby one learns that these molecules firstly will form intact, gas phase, anions and secondly that anions of the canonical neutral nucleosides are formed, while in the case of dAMPH- it is likely that in forming a negative ion an intramolecular proton transfer has occurred. Intermolecular proton transfer has also been studied fairly extensively by our group as a mechanism by which DNA strand breaks occur. In these cases the attachment of an electron drives an intermolecular proton transfer between a weak acid and a nucleic acid base.; Diffusely bound electron states of several varieties were studied. These are double Rydberg anions where a cationic core is surrounded by two diffuse electrons; here two new members of this family have been found. The dipole bound anions of ethylene carbonate, vinylene carbonate, and betaine have been formed and studied. Lastly, dipole bound and quadrupole bound anions of succinonitrile were observed depending on the conformation (trans or gauche) the succinonitrile molecule took.; Reactivity studies were done on the Al13- cluster; reacting it with HCl. Al13- is of interest because of its possible use in cluster-assembled materials. To further the understanding of the properties of this unique cluster, reactivity studies were carried out in order to assess its stability with respect to HCl. It was found that unlike its neighboring clusters Al13- did not react spontaneously with HCl, instead energy needed to be supplied in order for a reaction to occur.; Finally, silicon clusters were doped with the rare earth metals, gadolinium and holmium. The photoelectron spectra of GdSin -, n = 2-12, HoSi6- and HoSi12 - were recorded and plans are underway to continue filling out the holmium series as well as continue with additional rare earth metals.