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Gas-Phase Ion Chemistry: Kinetics and Thermodynamics

TitleGas-Phase Ion Chemistry: Kinetics and Thermodynamics
Publication TypeThesis
Year of Publication2016
AuthorsNichols, CM
Academic DepartmentDepartment of Chemistry and Biochemistry
Number of Pages169
Date Published02-2016
UniversityUniversity of Colorado
CityBoulder, CO

This thesis employs gas-phase ion chemistry to study the kinetics and thermodynamics of chemical reactions and molecular properties. Gas-phase ion chemistry is important in diverse regions of the universe. It is directly relevant to the chemistry occurring in the atmospheres of planets and moons as well as the molecular clouds of the interstellar medium. Gas-phase ion chemistry is also employed to determine fundamental properties, such as the proton and electron affinities of molecules. Furthermore, gas-phase ion chemistry can be used to study chemical events that typically occur in the condensed-phase, such as prototypical organic reactions, in an effort to reveal the intrinsic properties and mechanisms of chemical reactions. 

Mass spectrometry is used to investigate the reactivity and fundamental properties of ions. Kinetic data for reactions between cations or anions with neutral atoms or molecules is acquired using the selected ion flow tube (SIFT). These data are interpreted mechanistically and thermodynamically using literature data and theoretical computations. Additionally, the proton affinities of a series of anions are determined using a triple quadrupole mass spectrometer by investigating the collision induced dissociation of proton-bound, anionic heterodimers. 

The SIFT is coupled with a variety of ion-generation techniques. This thesis reports the design and operation of a new electrospray ion source for the SIFT in detail. The electrospray ionization technique allows ions that are pre-formed in the condensed phase to be transmitted into the gas-phase for studies of their reactivity.