Strong-field ionization leading to Coulomb explosion of small clusters

The strong-field interaction of electromagnetic radiation with matter is an important area of study for understanding the specific mechanisms of ionization. Chapter 1 introduces the topic of strong-field physics and the overall significance of clusters as well as different proposed mechanisms of strong-field ionization. Chapter 2 describes the overall setup of the femtosecond laser system that is utilized to carry out experiments of small, gas phase cluster systems. In addition, the overall scheme of intensity selective scanning is described. Chapter 3 discusses in detail how experimental data is modeled using a derivation of tunneling theory and how this is used to describe ionization enhancement processes.;Chapter 4 details strong-field ionization studies on chlorine weakly-bound to small water clusters. The observed ionization enhancement was quantified using semi-classical tunneling theory and it was found that the Cl 3+-5+ and O2+ charge states are enhanced in ionization. Possible mechanisms of ionization enhancement are explored for weakly-bound chlorine species.;Chapter 5 describes the growth and subsequent ionization mechanisms of small silicon clusters using different metal electron sources. The first half of the chapter explores the effect of using an early-group transition metal as an electron source in the formation of small silicon clusters on the observed enhancement in ionization. The second half of the chapter deals with the growth and ionization patterns of small silicon clusters by varying the metal electron source for cluster formation using group 10 transition metals.;Chapter 6 details the ionization behavior of small group 5 metal carbide clusters. More efficient Coulomb explosion was observed according to: Ta>Nb>V due to the larger mass of tantalum, the slower cluster expansion times, and lower ionization potentials of large atoms.Ionization enhancement is explored by comparison to semi-classical tunneling theory.;Chapter 7 explores the ionization and Coulomb explosion of group 10 metal oxide clusters. Results indicate that nickel oxide clusters undergo a greater extent of ionization enhancement as a result of multiple ionization mechanisms.;Chapter 8 describes strong-field ionization of small neodymium and europium oxide clusters. Neodymium was observed to show larger enhancements in ionization whereas larger gaps in ion signal between atomic charge states of europium charge states indicate a more sequential-like ionization process. Comparison of f-block actinides to niobium and tantalum oxide clusters showed similar trends in ionization that are directly related to the metal ionization potentials.;Chapter 9 looks at ionization and Coulomb explosion of small uranium oxide clusters.;Chapter 10 details the properties of so-called "superatom" compounds that mimic the electron configurations of atoms. The first half of the chapter details studies on small, neutral PdxOy and ZrxOy clusters. The second half of the chapter looks at the ionization behavior of small zirconium oxide, palladium oxide, tungsten carbide, and platinum clusters.;Chapter 11 studies the strong-field ionization properties of small (n<5) methane clusters produced using a copper electron source. (Abstract shortened by UMI.).