A crystal of infrared-grade potassium bromide (KBr) was cleaved in air using a clean single-edged razor blade. The crystal was adhered to double-sided adhesive tape and analyzed by XPS at an angle that maximizes the information associated with subsurface bulk. The crystal's dimensions were 3 mm × 3 mm × 10 mm (w×h×l), and only the freshly exposed surface was analyzed. A mesh made of nickel wire was placed about 1 mm above the surface of the sample to flatten the electric fields on the sample.