Special Physical Chemistry Seminar: Surface-specific spectroscopy from first principles

Abstract:

Our current understanding of the structure and dynamics of aqueous interfaces at the molecular level has grown substantially in the last few decades due to the continuous development of surface-specific spectroscopies, such as vibrational sum-frequency generation (VSFG). While VSFG provides valuable information on its own, only when it is combined with accurate atomistic simulations can a comprehensive microscopic picture emerge. In the first part of my talk, I will present our recent efforts towards the simulation of surface-specific spectroscopies from first principles using machine learning approaches [1]. Next, I will focus on the liquid/air interface of different aqueous electrolyte solutions [2]. I will clearly demonstrate that the textbook electric-double layer model is an incomplete microscopic picture to understand the interface of NaI, NaBr, NaCl, and NaF aqueous solutions and it is completely inappropriate for the NaOH and CsF cases. Based on our first principles simulations, we propose that the surface of most common electrolytes solutions is stratified into two water layers, one depleted and the other enriched with ions, creating an effective liquid-liquid interface buried a few Å inside the solution. 

[1] Y. Litman, J. Lan, Y Nagata, D. M. Wilkins, arXiv:2305.09321 (2023) (Under revision in Proc. Nat. Acad. Sci.)

[2] Y. Litman, K-Y. Chiang, T. Seki, Y. Nagata, M. Bonn, arXiv:2210.01527 (2022) (Under revision in Nat. Chem.)
 

Seminar Organizer: Prof. Haim Diamant & Dr. Barak Hirshberg