The importance of including coverage dependence or lateral interactions was recognized early on, and a detailed survey of this history is beyond the scope of the present work. Fowler and Guggenheim pointed out in 1939 the ineffectiveness of the ideal assumption and approximated the adsorbate interaction energy as a sum of pairwise contributions among nearest neighbors . The following year, Temkin proposed an adsorption model, the Temkin isotherm, in which the heat of adsorption is linearly dependent on surface coverage. More recently, researchers have advanced the physicochemical understanding of the coverage effects on transition metal surfaces. Building upon pioneering work theorizing the source of lateral interactions , a series of insightful studies has led to the elucidation of physics behind the coverage effects . The effects of coverage were observed experimentally both in adsorbate vibrational frequencies and binding energy in the form of changes in spectroscopic measurements and adsorption/desorption dynamics , respectively. The lateral interactions also have been observed experimentally through infrared spectroscopy (IR), low-energy electron diffraction (LEED), temperature-programmed desorption (TPD), auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS) .