Challenges in Interpreting Vibrational Sum Frequency Spectra: Deconvoluting Spectral Features as Demonstrated in the Calcium Fluoride—Water—Sodium Dodecylsulfate System

Vibrational sum frequency spectroscopy is used to examine the CaF 2 /H 2 O interface and the CaF 2 /D 2 O interface upon adsorption of the anionic surfactant sodium dodecylsulfate (SDS) onto the CaF 2 surface. Proper interpretation of the results from this coherent spectroscopic technique requires a meticulous understanding of the interferences that result between sharp CH stretching modes, broad OH stretching modes, and the nonresonant background. The reported studies demonstrate the appropriate spectral analysis procedure required for a correct interpretation of spectra of this type and the errors that can result from a more simplistic but commonly used analysis procedure.