RUI: Beyond Electrostatics: Investigating the Contributions of Dispersion and Electron Transfer in Intermolecular Interactions

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With this award, the Chemical Structure, Dynamics and Mechanisms (CSDM-A) Program of the Division of Chemistry is funding Professors Helen O. Leung and Mark D. Marshall of Amherst College and their undergraduate student researchers to investigate the fundamental nature of the forces between molecules. The ultimate goal of this research is to develop more fully the understanding of intermolecular interactions, how they are affected by, and in turn how they affect the first encounters between molecules. The undergraduate researchers working on this project receive significant research experiences in an active physical chemistry laboratory as part of a their liberal arts and sciences education and are given the opportunity to present their work at scientific conferences. This raises the scientific literacy and sharpens the thoughts of student participants, preparing them as future scientists.Intermolecular interactions are investigated through the analysis of rotational spectra obtained using Fourier transform microwave (FTMW) techniques. The availability of two types of FTMW spectrometers (chirped pulse and Balle-Flygare) provides key research and pedagogic advantages as well as enhancing undergraduate participation in scientific research. The determination of the structures of a series of gas-phase dimeric complexes, in combination with ab initio quantum chemistry calculations, provides information regarding the nature of the forces responsible. Specifically, complexes formed between protic acids and haloethylenes reveal the effects of dispersion interactions on intermolecular association. The laser ablation technique is used to generate metal containing complexes in which electron transfer is expected to play a role, and effects of intermolecular interactions on the electron density of the hydroxyl (OH) radical are studied using complexes involving this open-shell species.