On Second-Order Vibrational Lineshapes of the Air/Water Interface
Abstract
We explore by means of modeling how absorptive-dispersive mixing between the second- and third-order terms modify the imaginary chi(2)total responses from air/water interfaces under conditions of varying charge densities and ionic strength. To do so, we use published Im(chi(2)) and chi(3) spectra of the neat air/water interface that were obtained either from computations or experiments. We find that the chi(2)total spectral lineshapes corresponding to experimentally measured spectra contain significant contributions from both interfacial chi(2) and bulk chi(3) terms at interfacial charge densities equivalent to less than 0.005% of a monolayer of water molecules, especially in the 3100 wavenumber to 3300 wavenumber frequency region. Additionally, the role of short-range static dipole potentials is examined under conditions mimicking brine. Our results indicate that surface potentials, if indeed present at the air/water interface, manifest themselves spectroscopically in the tightly bonded H-bond network observable in the 3200 wavenumber frequency range.
Keywords
Cite
@article{arxiv.1712.09086,
title = {On Second-Order Vibrational Lineshapes of the Air/Water Interface},
author = {Paul Ohno and Hong-fei Wang and James Skinner and Francesco Paesani and Franz M. Geiger},
journal= {arXiv preprint arXiv:1712.09086},
year = {2018}
}
Comments
Pre-edited version, 21 pages, 3 figures, supporting information available upon request