Disentangling Many-Body Effects and Coupling in the Vibrational Spectra of Aqueous Clusters

With support from the Chemical Structure, Dynamics, and Mechanism A program of the Division of Chemistry, Professors Francesco Paesani (University of California – San Diego) and Ryan Steele (The University of Utah) will collaboratively investigate the manner in which charged particles, called ions, interact with water. This hydration of ions drives numerous processes, including biological chemistry, atmospheric chemistry, and renewable-energy chemistry.

The response of these chemical species to infrared light provides clues regarding their behavior, but unraveling the details of this behavior from experiments often requires large-scale computer simulations. The two research groups will use new computer simulations to study, at the atomic level, the processes that govern these ion-water interactions.

In parallel, the investigators will be involved in outreach and mentoring activities designed to promote science, technology, engineering, and mathematics (STEM) disciplines among students from underrepresented groups. In particular, Professor Paesani will focus on integrating UC San Diego and San Diego community college students in research projects throughout the academic year.

Professor Steele will focus on mentoring high-school chemistry teachers through M.S. Program for Secondary School Teachers at the University of Utah as well as in the integration of computational simulations into the high school curriculum.

The two research groups will combine newly developed many-body potential energy functions with new local-mode approaches for simulating anharmonic vibrational spectroscopy. This synergy will enable the decomposition of the anharmonic couplings that drive unique vibrational behavior in strong ions and provide insight to recent hydrated-ion experiments.

The impact of divalent ions on hydrogen-bonding networks will also be investigated, along with the evolution of hydration behavior of small biomolecular ions. Wherever possible, these investigations will be coupled with recent and forthcoming results from experimental collaborators. Ultimately, these studies will be used to calibrate the potential energy functions and their underlying physics, in order to simulate both small, hydrated ions and condensed-phase solutions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.