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O: Fachverband Oberflächenphysik

O 62: Poster Session V: Organic molecules on inorganic substrates: electronic, optical and other properties I

O 62.4: Poster

Wednesday, March 3, 2021, 10:30–12:30, P

Benchmarking ab-initio methods to predict non-adiabatic charge transfer at metal-organic interfaces — •Daniel Corken, Nicholas D.M. Hine, and Reinhard J. Maurer — University of Warwick, Coventry , United Kingdom

State-resolved molecular beam scattering experiments have shown that small molecules scattering from metal surfaces exhibit non-adiabatic behaviour whereby charge is dynamically transferred from the metal to the molecule, creating a transient anion. Understanding chemical dynamics of molecule-metal systems is essential for designing the next generation of heterogeneous catalysts. Such dynamical non-adiabatic charge-transfer is not captured by ground state Density Functional Theory or classical dynamics and the explicit anionic excited-state and coupling constants between states need to be described. Metal-organic interfaces feature a continuum of electronic states rendering conventional excited state methods prohibitively expensive. Here we assess three approximate and computationally efficient methods to predict excited states at metal surfaces: The use of an applied electric field, constrained DFT, and the linear-expansion-Delta-Self-Consistent-Field method. For the prototypical system of CO on Au(111), we compare the methods based on how accurately they predict excited-state energy landscapes and their computational efficiency and numerical robustness, with the aim to identify an excited state method to perform non-adiabatic dynamics simulations for charge transfer systems in the future.