Computational Chemistry Commons^™

Investigating Dna Damage Caused By Reactive Oxygen And Nitrogen Species Via Guided-Ion-Beam Scattering And Computational Techniques, Jonathan Benny

Dissertations, Theses, and Capstone Projects

Among DNA nucleobases, guanine (G) is the primary target for one-electron ionization and oxidation, generating G●+ through various processes, including photooxidation, electrocatalytic oxidation, DNA-binding transition metals, ionizing radiation, and photolysis. This is due to the low adiabatic ionization potential and oxidation potential of guanine. Electron holes from other nucleobases can move to guanine, proving that G●+ production traps oxidative DNA damage. G●+ formation can exacerbate DNA damages and cause secondary reactions from reactive oxygen species (ROS) and reactive nitrogen species (RNS) during pathological processes. The following three projects were conducted using a customized electrospray ionization (ESI) guided-ion-beam tandem mass spectrometer, …

Unraveling The Reactivity Of Nitrate Ester Explosives: Insights From Femtosecond Time-Resolved Mass Spectrometry And Computational Chemistry, Erica Britt

Theses and Dissertations

This dissertation uncovers the ultrafast molecular mechanisms underlying the decomposition of nitrate ester explosives—nitroglycerin (NG), ethylene glycol dinitrate (EGDN), and amyl nitrate—through the integration of femtosecond time-resolved mass spectrometry and advanced computational chemistry. Although these compounds play fundamental roles in both military and civilian contexts, the precise molecular dynamics governing their pronounced reactivity and impact sensitivity have remained inadequately characterized. Our research establishes that low O–NO2 bond dissociation energies are the primary driver of ultrafast fragmentation and high reactivity in all three esters. The distinctive molecular architectures of these esters dictate their explosive properties: NG’s tri-nitrate configuration leads to exceptional …

Intrinsic Gas-Phase Behavior Of Uranium Species: A Comprehensive Reactivity Study Of [O=U≡Ch]+ And [Uh]+, Justin Terhorst

Electronic Theses and Dissertations

The intrinsic chemistry of actinide elements, particularly uranium, remains a key challenge in understanding f-block reactivity due to the complexity introduced by solvent interactions, counter-ions, and complex equilibria in the condensed phase. In this dissertation, a systematic gas-phase study utilizing preparative tandem ion-trap mass spectrometry (PTMSⁿ) is presented, focusing on the reactivity of uranium-centered species, specifically [OUCH]⁺, an oxy uranium methylidyne species, and [UH]⁺ ions. By stripping away solvent effects and isolating the ions, PTMSⁿ provides a powerful platform to probe the fundamental chemical behavior of uranium species in their intrinsic state.

The …

Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques For Analysis Of Energetic Materials, Shane L. Mcpherson

Theses and Dissertations

Energetic materials and the unimolecular dissociation dynamics attributed to their initiation and subsequent bimolecular detonation have been a subject of interest for defense agencies such as the Department of Defense (DoD) for decades. The timescale in which these initial dynamics exist ranges from several picoseconds to dozens of femtoseconds, necessitating equally fast time-resolved experiments to capture and characterize these events. Our lab specializes in one such laser-based technique: femtosecond time-resolved mass spectrometry (FTRMS). FTRMS is an essentially nondiscriminatory pump-probe laser technique with nearly infinite modifications via pulse shaping, intensity, and wavelength modulation that can readily examine previously undefined dissociation pathways …