Pinning Down the Elusive Nature of the Hydrated Electron: A Comprehensive Assessment of Cavity, Non-Cavity, and Hybrid Models

Seminar series
Physical Chemistry Seminar
Thu, May 15 12:00pm
2033 Young Hall
Speaker Jennifer R. Casey
University of California, Los Angeles
Dept. of Chemistry and Biochemistry

Abstract: The hydrated electron, which is an excess free electron solvated in liquid water, is a system of great interest due to its appearance in various fields ranging from biology to radiation chemistry. The hydrated electron has been studied both experimentally and theoretically for many decades, and the prevailing model is that the electron resides in a cavity.  Recently, our group challenged this concept of the hydrated electron by presenting evidence for a hydrated electron that occupies a region of enhanced water density; the electron in this alternate picture has predicted properties that agree well with experiment. In this talk, we turn to additional mixed quantum classical (MQC) calculations that help determine which picture for the hydrated electron more closely aligns with experiment, whether it be a cavity electron, a non-cavity electron, or an electron that is a hybrid of the two. Specifically, we investigate how well different hydrated electron models predict the temperature dependence of the hydrated electron’s absorption spectrum and the resonance Raman spectrum of the electron. We also have explored the behavior of hydrated electrons at the air/water interface, since this could lead to further differentiation amongst these various models. In the end, our calculations suggest that the non-cavity picture of the hydrated electron may provide a better description than the older picture based on the hydrated electron occupying a cavity.