Calorimetric Measurement of the Energy Difference Between Two Solid Surface Phases

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Science  23 Jun 1995:
Vol. 268, Issue 5218, pp. 1731-1732
DOI: 10.1126/science.268.5218.1731


A recently designed single-crystal surface calorimeter has been deployed to measure the energy difference between two solid surface structures. The clean Pt{100} surface is reconstructed to a stable phase in which the surface layer of platinum atoms has a quasi-hexagonal structure. By comparison of the heats of adsorption of CO and of C2H4 on this stable Pt{100}-hex phase with those on a metastable Pt{100}-(1x1) surface, the energy difference between the two clean phases was measured as 20 ± 3 and 25 ± 3 kilojoules per mole of surface platinum atoms.