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STRUCTURAL AND DYNAMIC PROPERTIES OF GAS-PHASE MOLECULES IN HIGH-ORDER HARMONIC GENERATION: INSIGHTS FROM TIME-DEPENDENT DENSITY FUNCTIONAL THEORY CALCULATIONS
No full textHigh-order harmonic generation, or HHG, is a highly nonlinear quantum optical process capable of generating X-ray/ultraviolet radiation. An atom or molecule is irradiated with a mid-IR laser at high intensity, ionizes, and then emits high-frequency light at integer multiples of the driving laser frequency when an ionized electron recollides with the molecular ion. A convenient tabletop source of coherent XUV light and a common seed for free-electron lasers, HHG can also serve as a self-probe of the source atom or molecule. In the latter case, the HHG spectrum can provide valuable insight into the structure and dynamics of the species in a strong field. Certain features, particularly minima, maxima, and lineshape, are indicative of various processes related to recombination and chemical structure. In this thesis, the calculated high-resolution HHG spectra of small molecules are explored in-depth to uncover their structure and behavior in a strong electric field. When high-resolution laser conditions are selected, molecular HHG spectra calculated using Time-Dependent Density Functional Theory with Generalized Pseudospectral Method reveal previously unobserved strong-field structural and dynamic features of the target molecules.
In Chapter 1, the concept of high-order harmonic generation is described in detail as it applies to this research; to introduce the theory in Chapter 2, Chapter 2.1 introduces the concept of density functional theory methods, which are central to the calculated results herein; Chapter 2.2 extends these principles to time-dependent density functional theory, the basis for generating HHG spectra in this work; Chapter 2.3 links the concepts in Chapter 2.2 to Generalized Pseudospectral Method, which is necessary here for the time propagation; Chapter 3 discusses the calculated HHG results for acetylene and Chapter 4 covers the results for lithium hydride; finally, conclusions and future directions are outlined in Chapter 5
Building Bridges: Professional Journey into Social Work
No full textThis portfolio highlights my development as a social work practitioner and demonstrates the knowledge, skills, and values I have gained throughout my MSW program. It showcases my work across micro, mezzo, and macro levels, including assessments, case management, policy analysis, ethical reflections, and advocacy projects.https://scholarworks.umt.edu/grad_portfolios/1524/thumbnail.jp
How Perceptions of Trauma Impact the Relationship Between Adverse Childhood Events and Drinking Habits of College Students
No full textAdverse Childhood Experiences (ACEs) have been consistently linked to alcohol misuse across the lifespan; however, little research has examined how individuals’ perceptions of these experiences contribute to risky drinking behaviors. The present study investigated the associations among ACEs, perceived traumatic impact of childhood adversity, gender identity, and alcohol use among 211 undergraduate students ages 18 to 25 at the University of Montana (Missoula). Participants completed measures assessing ACE exposure, perceived trauma impact, depressive symptoms (PHQ-9), adult adverse experiences, and alcohol use (AUDIT). ACE scores significantly predicted higher AUDIT scores in an unadjusted model; however, this relationship was no longer significant after controlling for depressive symptoms, adult trauma exposure, and access to mental health services. Perceived trauma impact similarly predicted AUDIT scores in an unadjusted model but did not remain significant after controlling for ACEs and covariates. Binary gender identity did not account for significant variance in AUDIT scores after controlling for ACEs and covariates. Gender diversity accounted for a small, trend-level increase in risky drinking, suggesting potential elevated risk among gender-diverse students, though interpretation is limited by the small number of gender-diverse participants. Across all models, depressive symptoms emerged as the most consistent predictor of risky drinking amongst emerging adults. These findings suggest that although ACEs and perceived trauma are associated with risky alcohol use, their effects may be explained or mediated by co-occurring depressive symptoms. Implications for college mental health services and trauma-informed prevention efforts are discussed
FUEL TREATMENT EFFECTIVENESS IN THE MESIC NORTHERN ROCKY MOUNTAINS
No full textFire severity in mesic mixed-conifer forests is shaped by complex interactions among climate, weather, fuels, and topography, yet treatment effectiveness in these systems remains poorly quantified across broad landscapes. We evaluated drivers of burn severity and fuel treatment effectiveness across four Northern Rocky Mountain ecoregions (Canadian Rockies, Idaho Batholith, Middle Rockies, and Northern Rockies) using an empirical, landscape-scale modeling framework. We compiled burn severity, treatment history, and environmental predictors for 700 wildfires (2001–2023), and developed Random Forest models using both gridded weather (gridMET) and higher-resolution TopoFire predictors. Treatment effectiveness was evaluated using matched-control comparisons and a counterfactual approach that estimated expected severity under a no-treatment scenario. Across ecoregions, fire severity was most strongly regulated by climate and short-term weather conditions, particularly predictors related to fuel moisture (e.g., dead fuel moisture, soil moisture, and climate water deficit), while static topographic and fuel metrics played secondary, context-dependent roles. Elevation was the only topographic predictor consistently ranked among the strongest variables, likely reflecting covariation with bioclimatic gradients rather than independent controls on fire behavior. Incorporating higher-resolution TopoFire weather data modestly improved representation of within-fire variability but did not substantially improve model performance or transferability to independent fires, underscoring challenges in generalizing severity models across heterogeneous landscapes. Treatment effectiveness varied by treatment type, age, ecoregion, and evaluation method. Combined treatments that reduced both canopy and surface fuels—particularly removal + surface reduction and removal + prescribed fire—showed the most consistent reductions in severity. In several categories, older treatments occasionally reduced severity more than recent treatments, suggesting that treatment longevity in mesic forests may be mediated by fuelbed decomposition and moisture dynamics. Across the study extent, prior wildfire and prescribed fire comprised the largest treatment footprints within subsequent wildfire perimeters, indicating that wildfire itself is a dominant driver of landscape fuel modification. These findings highlight the context dependence of treatment outcomes in mesic forests and support evaluation frameworks that integrate counterfactual modeling and broader management objectives beyond severity reduction
