DESIGN AND PERFORMANCE OF A NEW INFRARED REFLECTION ACCESSORY FOR SPECTROELECTROCHEMICAL STUDIES

A novel spectroelectrochemical cell based on a hemispherical window wh ich fits in the sample compartment of a center-focus FT-IR spectromete r is described. The ZnSe hemisphere serves to collimate the beam, prov ide near-critical angle reflection, lower first-surface reflection los ses, and reestablish the instrument focal point. The optics of the spe ctroelectrochemical accessory include only two folding mirrors, the IR polarizer, the ZnSe window, and the electrode. The optimum angle of i ncidence for the reflection experiment is determined from calculated m ean-squared electric field strengths. Typical potential difference spe ctra are presented for varying degrees of signal optimization, and the gains in signal-to-noise ratios are reported.