Weber Research Group ^{Ion Spectroscopy}

Intellectual Merit

Transition metal complexes are important chemical species for many processes, ranging from homogeneous and heterogeneous catalysis to solar energy conversion. Gas-phase ion-molecule complexes can serve as model systems for studying ion-molecule interactions and yield much information about their analogues in condensed-phase chemistry. Although anionic complexes are very important, e.g. in heterogeneous catalysis at metal oxide surfaces or as starting materials for metal nanoparticles in solution-phase, most of the information on gas-phase species is on cationic complexes. Mass spectrometry and photoelectron spectroscopy data have provided a good foundation of basic knowledge in this field, but there is a need for better spectroscopic experimental data with more information content than either mass spectrometry of photoelectron techniques on anionic species can deliver, despite their great successes.

The primary goal of the proposed work is to use spectroscopic tools to obtain a more detailed picture of transition metal chemistry, and to understand the role of negative charge in the context of transition metal containing complexes. Weber and his group are interested in gaining a deeper insight into the electronic and geometric structures, and the inter- and intramolecular forces in transition metal complex ions, which will be studied by infrared and electronic photodissociation spectroscopy. The experiments will uncover valuable information e.g. on the electron donation/back-donation in metal- and metaloxide-ligand complexes and electron binding energies. In addition, they will shed more light on the electronic structure of singly and multiply charged metalates [M_nX_m]^k- (M = metal; X = halide) as a function of coordination and size, where the spectra contain information on possible new routes for nanoparticle production. The interpretation of the experiments will be aided by quantum chemical calculations.

In the educational part of this proposal, Weber plans to perform education research on how undergraduate chemistry students learn quantum mechanics as part of the Science Education Initiative at CU Boulder. He will use the results to transform the undergraduate course on quantum mechanics and its applications in chemistry to be more aligned with the principles of student learning, and develop curricular material and assessment tools.

Broader Impacts:

The interaction of transition metals with ligands plays an important role e.g. in industrial processes, materials chemistry, and in the context toxic environmental impact of transition metals. Advancing the basic understanding of transition metal chemistry can aid in a better understanding of catalysis and in harnessing photochemical routes to solar energy use in transition metal catalysts, sequestration of harmful substances and greenhouse gases (e.g. CO₂). Other possible technological impacts are the discovery of new pathways to photochemical nanoparticle generation.

Additionally, the proposed work has important educational aspects. The experiments will be performed by undergraduate and graduate students, providing them with unique opportunities to be trained in instrument development, spectroscopy, and mass spectrometry. The educational activities in this proposal will yield deeper insight and transform how chemistry and biochemistry undergraduate students learn quantum mechanics. At CU Boulder, this effort will impact about 100-150 students every year. In addition, these activities will result in curricular material and instructor resources that can be used beyond CU Boulder, laying the foundation for the transformation of how chemistry students learn quantum mechanics with an impact on the national level.

As an additional outreach activity, the PI will develop a lecture for the enormously successful CU Wizards program, a continuing Saturday morning lecture series that introduces topics in astronomy, chemistry, engineering, and physics, and is intended primarily for students in grades five through nine.