Figure 5: Separation and comparison of binding energy changes due to mechanical and electronic contributions.
From: Mechanical work makes important contributions to surface chemistry at steps
(a) Conceptual separation of the binding energy into an electronic contribution, ΔEelec, due to adsorbate–surface electronic interactions, and a mechanical contribution, ΔEmech, due to structural relaxations upon chemisorption on the strained substrate (distortions exaggerated for emphasis); also shown is the reverse process with corresponding energies ΔE′elec and ΔE′mech, which should have the same trends under loading and with ΔE′mech clearly mechanical in origin. (b) Absolute magnitude of the electronic contribution versus the mechanical contribution, |ΔEelec| versus |ΔEmech|, for CO on various substrates, showing that the mechanical contributions are typically larger than or comparable to the electronic contributions (squares: σbiax; triangles σ[01–1]; circles: σ[−111]; the color indicates the element as inset). (c) Reverse mechanical contribution ΔE′mech versus forward mechanical contribution ΔEmech, showing that ΔEmech=ΔE′mech holds well (and therefore ΔEelec=ΔE′elec). Dashed line indicates ΔEmech=ΔE′mech and is a guide to the eye. Descriptions of strain state and element in (supplementary Fig 7a).
