Structure, Dynamics and Vibrational Spectroscopy of Aqueous Surfaces and Interfaces

We will present our recent theoretical work on structure, dynamics and nonlinear vibrational spectroscopy of aqueous surfaces and interfaces using a combination of molecular dynamics simulations, quantum calculations and machine learning methods. Specifically, we will present calculations of one-dimensional and two-dimensional vibrational sum frequency generation (1D-VSFG and 2D-VSFG) spectral calculations of water in the mid-IR region for different interfacial systems. The results of various dynamical features of the two-dimensional spectra are connected to various underlying dynamical modes of the systems such as librational motion, hydrogen bond stretch, hydrogen bond breaking and also conversion between hydrogen bonded and dangling (non-hydrogen bonded) states of OH modes. We will also discuss structure and VSFG spectrum of aqueous systems near mineral surfaces at different pH conditions.