Water on MgO(1 0 0)—An infrared study at ambient temperatures

Transmission Fourier transform infrared spectroscopy (FTIR) is used to investigate water adsorbed on the (1 0 0) face of MgO under ambient conditions. From these measurements, we find that water reversibly adsorbs to MgO(1 0 0) creating liquid-like layers at temperatures ranging from −10 °C to 40 °C with slight hysteresis seen during a complete adsorption/desorption cycle. The adsorption isotherms of water on MgO(1 0 0), throughout the entire temperature range sampled, resemble a typical BET plot, which coupled with the fact that IR absorption due to the OH stretch of the adsorbed water does not change as a function of coverage, suggests that the layer grows in via three-dimensional island formation. Thermodynamic analysis indicates three distinct regions of water adlayer growth.