"On-the-fly" calculation of the Vibrational Sum-frequency Generation Spectrum at the Air-water Interface

TL;DR

This paper introduces an electronic structure-based method for real-time calculation of vibrational sum-frequency generation spectra at the air-water interface, capturing key vibrational modes.

Contribution

It presents a novel on-the-fly computational scheme combining Wannier functions to predict v-SFG spectra from electronic structure data.

Findings

Successfully demonstrated at the air-water interface

Captures hydrogen bond vibrational signatures

Provides a computationally efficient approach

Abstract

In the present work, we provide an electronic structure based method for the "on-the-fly" determination of vibrational sum frequency generation (v-SFG) spectra. The predictive power of this scheme is demonstrated at the air-water interface. While the instantaneous fluctuations in dipole moment are obtained using the maximally localized Wannier functions, the fluctuations in polarizability are approximated to be proportional to the second moment of Wannier functions. The spectrum henceforth obtained captures the signatures of hydrogen bond stretching, bending, as well as low-frequency librational modes.