Second-Order Vibrational Lineshapes from the Air/Water Interface

Paul E. Ohno, Hong Fei Wang, Francesco Paesani, James L. Skinner, Franz M. Geiger*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


We explore by means of modeling how absorptive-dispersive mixing between the second- and third-order terms modifies the imaginary χtotal(2) responses from air/water interfaces under conditions of varying charge densities and ionic strength. To do so, we use published Im(χ(2)) and χ(3) spectra of the neat air/water interface that were obtained either from computations or experiments. We find that the χtotal(2) spectral lineshapes corresponding to experimentally measured spectra contain significant contributions from both interfacial χ(2) and bulk χ(3) terms at interfacial charge densities equivalent to less than 0.005% of a monolayer of water molecules, especially in the 3100 to 3300 cm-1 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 cm-1 frequency range.

Original languageEnglish (US)
Pages (from-to)4457-4464
Number of pages8
JournalJournal of Physical Chemistry A
Issue number18
StatePublished - May 10 2018

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry


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