Orbital interactions on surfaces from First-Principles

Electronic coupling and overlap matrix elements are routinely used to describe phenomena on surfaces such as electron transfer and chemisorption. Typically, these parameters are approximated or shown qualitatively as orbital diagrams. Using a recently developed diabatization method [1], we calculate adsorbate-surface matrix elements quantitatively from first-principles Density Functional Theory. The resulting parameters are then used to populate physical models, such as the Fermi Golden Rule or Newns-Anderson model [2].



We demonstrate the approach by calculating electron transfer lifetimes for adsorbates on metal surfaces, comparing to measurements from ultrafast core-hole clock spectroscopy and Scanning Tunneling Spectroscopy. We find quantitative agreement with measurements over timescales ranging from attoseconds to nanoseconds. In both cases, the use of first-principles couplings is found to elucidate nontrivial phase cancellation effects which are known to complicate the interpretation of these measurements. Finally, we apply the approach to study trends in chemisorption on transition metal surfaces, with an eye on identifying descriptors for materials design [3].



[1] S. Ghan et al., J. Chem. Phys. 158, 234103 (2023).

[2] D.M. Newns, Phys. Rev. 178, 3, 1124 (1969).

[3] D.M. Patel, S. Ghan et al., Electrochimica Acta 543, 147476 (2025).