RUI: Double Photoionization to Probe Electron Correlation in Molecular Targets with more than Two Electrons

California Maritime Academy, Vallejo CA

Investigators

Abstract

The behavior of electrons in atoms and molecules is fundamental to our understanding of material systems. From the basic chemical bonds that hold molecules together to the bulk properties of macroscopic matter, electrons are largely responsible for the chemical makeup and physical properties of liquids and solids. Quantum mechanics has informed us of the true nature of matter at the small scale of the atom, but accurately representing even the simplest molecule is challenging. Still, there is much to be learned from studying matter at the most fundamental level, including a better understanding of the consequences of electron correlation that govern so much of how matter behaves at all length scales. Electron correlation goes beyond the fact that electrons repel each other; electrons continually notice each other in fundamental ways, like spin interactions, and learning about those interactions better informs us of the fundamental construction of our universe. Double photoionization studies, where a photon of sufficient energy can remove two electrons from a material in a single event, directly probes electron correlation. This research will advance precise methods to describe double photoionization in molecules with many electrons, like water (H2O). The purpose is to better understand electron correlation in these more-complicated targets and gain further general insights into the fundamental interactions of electrons in molecules. This understanding, once developed, informs multiple technological applications involving chemistry and materials that are essential to a high-tech society. This project will investigate electronic correlation for two electrons removed by single-photon absorptions (double photoionization) for simple molecules with more than two electrons in order to better understand the ways that multi-electron targets are influenced by additional complexity (beyond H2). Theoretical calculations describing these events from first principles will be applied to targets with many electrons that continue to interact with the fully correlated electrons before, during and after the photoionization event. Theoretical support is needed to help inform and understand recent experimental measurements of double photoionization of water. It is hoped that this project can further elucidate the broader consequences of how all of the electrons bound to a molecule can affect those that will be moved into the continuum and how consequences of molecular symmetry and electronic structure impact the outgoing electrons from a molecular environment. 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.