Third-order effects in resonant sum-frequency-generation signals at electrified metal/liquid interfaces

Citation

Koelsch, Patrick; Muglali, Mutlu; Rohwerder, Michael; & Erbe, Andreas (2013). Third-order effects in resonant sum-frequency-generation signals at electrified metal/liquid interfaces. Journal of the Optical Society of America. B, Optical physics, 30(1).

Abstract

Vibrational sum-frequency-generation (SFG) spectroscopy experiments at electrified interfaces involve incident laser radiation at frequencies in the IR and near-IR/visible regions as well as a static electric field on the surface. Here we show that mixing the three fields present on the surface can result in third-order effects in resonant SFG signals. This was achieved for closed packed self-assembled monolayers (SAMs) with molecular groups of high optical nonlinearity and surface potentials similar to those typically applied in cyclic voltammograms. Broadband SFG spectroscopy was applied to study a hydrophobic well-ordered araliphatic SAM on a Au(111) surface using a thin-layer analysis cell for spectro-electrochemical investigations in a 100 mM NaOH electrolyte solution. Resonant contributions were experimentally separated from non-resonant contributions of the Au substrate and theoretically analyzed using a fitting function including third-order terms. The resulting ratio of third-order to second-order susceptibilities was estimated to be [Formula: see text](10(-10)) m/V.

Reference Type

Journal Article

Secondary Title

Journal of the Optical Society of America. B, Optical physics

Author(s)

Koelsch, Patrick
Muglali, Mutlu
Rohwerder, Michael
Erbe, Andreas

Year Published

2013

Date Published

1356998400

Volume Number

Issue Number

DOI

10.1364/josab.30.000219