Sample cells for probing solid/liquid interfaces with broadband sum-frequency-generation spectroscopy

• Published in: Review of scientific instruments Vol. 81; no. 6; p. 063111
• Main Authors: Verreault, Dominique, Kurz, Volker, Howell, Caitlin, Koelsch, Patrick
• Format: Journal Article
• Language: English
• Published: United States 01.06.2010
• Subjects: Acrylic Resins - chemistry; Algorithms; Equipment Design; Gold - chemistry; Metals - chemistry; Nonlinear Dynamics; Polymers - chemistry; Signal Processing, Computer-Assisted; Solutions - chemistry; Spectrum Analysis - instrumentation; Spectrum Analysis - methods; Temperature; Time Factors; Tin Compounds - chemistry; Water - chemistry
• ISSN: 1089-7623
• DOI: 10.1063/1.3443096

Two sample cells designed specifically for sum-frequency-generation (SFG) measurements at the solid/liquid interface were developed: one thin-layer analysis cell allowing measurement of films on reflective metallic surfaces through a micrometer layer of solution and one spectroelectrochemical cell allowing investigation of processes at the indium tin oxide/solution interface. Both sample cells are described in detail and data illustrating the capabilities of each are shown. To further improve measurements at solid/liquid interfaces, the broadband SFG system was modified to include a reference beam which can be measured simultaneously with the sample signal, permitting background correction of SFG spectra in real time. Sensitivity tests of this system yielded a signal-to-noise ratio of 100 at a surface coverage of 0.2 molecules/nm(2). Details on data analysis routines, pulse shaping methods of the visible beam, as well as the design of a purging chamber and sample stage setup are presented. These descriptions will be useful to those planning to set up a SFG spectrometer or seeking to optimize their own SFG systems for measurements of solid/liquid interfaces.