Combining research in physical chemistry and chemical education: Part A. The femtosecond molecular dynamics of small gas-phase anion clusters. Part B. Surveying student beliefs about chemistry and the development of physical chemistry learning tutorials.

摘要

This dissertation combines work in the areas of experimental physical chemistry and chemical education. In the area of physical chemistry, femtosecond pump-probe spectroscopy is used to interrogate the time-dependence for energy redistribution, solvent reorientation, and dissociation dynamics in small gas-phase anion clusters. The chemical education research addressed in this manuscript include the development and validation of a survey to measure students' beliefs about chemistry and the learning of chemistry and the development and testing of learning tutorials for use in undergraduate physical chemistry courses in thermodynamics and kinetics.; In the first part of this dissertation, the Cu(CD3OD) dynamics are investigated using a combination of femtosecond pump-probe experiments and ab initio calculations. Dissociation of this complex into Cu and CD3OD occurs on two distinct time scales: 3 and 30 ps, which arise, respectively, from the coupling of intermolecular solvent rotations and excited methyl rotor rotation into the Cu-O dissociation component upon electron photodetachment of the precursor anion.; In the second part of this dissertation, the time-resolved recombination of photodissociated IBr-(CO2)n (n = 5 - 10) cluster anions is investigated. Upon excitation to the A' 2pi 1/2 state of the chromophore, the bare anion results in I- and Br products, upon solvation with CO2, the IBr- chromophore regains near-IR absorption after recombination and vibrational relaxation on the ground electronic state. The recombination times vary with the number of solvent molecules from 12 ps for n = 5 to 900 ps for n = 10. Extensive electronic structure and non-adiabatic molecular dynamic simulations provide a framework to understand this behavior.; In the third part of this dissertation, the modification and validation of the Colorado Learning Attitudes about Science Survey (CLASS) for use in chemistry is presented in detail. The CLASS survey is designed to measure student beliefs about chemistry and the learning of chemistry. This instrument is a modification of the original CLASS-Phys survey designed for use in physics. Statements on the chemistry version (CLASS-Chem) are validated using chemistry students with a broad range of experience levels to ensure clarity in wording and meaning. The chemistry version addresses additional belief areas important in learning chemistry but not physics, specifically, beliefs about reactions and molecular structure. Statements are grouped into statistically robust categories using reduced basis factor analysis.; The final part of this dissertation addresses the development and testing of learning tutorials for use in undergraduate physical chemistry. The tutorials are designed to promote the active mental engagement of students in the process of learning. Questions within the pencil-paper format guide students through the reasoning needed to apply concepts to real-world situations. Each tutorial is connected to a physical model or computer simulation providing students with additional hands-on investigations to strengthen their connection with the concepts addressed in the tutorial. Currently tutorials connected with the First and Second Laws of Thermodynamics as well as Kinetics have been developed and tested.