The Nuts and Bolts of Ab-Initio Core-Hole Simulations for K-shell X-Ray Photoemission and Absorption Spectra

B. Klein, S. J. Hall, R. J. Maurer, J. Phys. Condens. Matter 33, 154005 (2020)

"We present the numerical and technical details of our variants of the DeltaSCF and transition potential method (coined DeltaIP-TP) to simulate XPS and NEXAFS transitions. Using exemplary molecules in gas-phase, in bulk crystals, and at metal-organic interfaces, we systematically assess how practical simulation choices affect the stability and accuracy of simulations. We particularly focus on the choice of aperiodic or periodic description of systems and how spurious charge effects in periodic calculations affect the simulation outcomes. For the benefit of practitioners in the field, we discuss sensible default choices, limitations of the methods, and future prospects."

Determining the effect of hot electron dissipation on molecular scattering experiments at metal surfaces

C. L. Box, Y. Zhang, R. Yin, B. Jiang, R. J. Maurer, JACS Au 1, 164-173 (2020)

"Vibrational state-to-state scattering of NO on Au(111) provides a testing ground for developing various nonadiabatic theories, including electronic friction theory. This system is often cited as the prime example for the breakdown of electronic friction theory, a very efficient model accounting for dissipative forces on metal-adsorbed molecules due to the creation of electron-hole-pair excitations in the metal. Here we present a comprehensive quantitative analysis of the performance of molecular dynamics with electronic friction (MDEF) in describing vibrational state-to-state scattering of NO on Au(111) and connect directly to fundamental approximations. Our analysis provides a firm baseline for the future development of nonadiabatic dynamics methods to tackle problems in surface chemistry and photocatalysis."

Alkali Doping Leads to Charge-Transfer Salt Formation in a Two-Dimensional Metal-Organic Framework

P. J. Blowey, B. Sohail, L. A. Rochford, T. Lafosse, D. A. Duncan, P. T. P. Ryan, D. A. Warr, T.-L. Lee, G. Costantini, R. J. Maurer, and D. P. Woodruff, ACS Nano 14, 7475-7483 (2020)

"We show that the insertion of alkali atoms can significantly change the structure and electronic properties of a metal-organic interface. Coadsorption of tetracyanoquinodimethane (TCNQ) and potassium on a Ag(111) surface leads to the formation of a two-dimensional charge transfer salt, with properties quite different to those of the two-dimensional Ag adatom TCNQ metal-organic framework formed in the absence of K doping. We establish a highly accurate structural model by combination of quantitative XSW, STM, and DFT calculations. Full agreement between the experimental data and the computational prediction of the structure is only achieved by inclusion of a charge-transfer-scaled dispersion correction in the DFT, which correctly accounts for the effects of strong charge transfer on the atomic polarizability of potassium. "

Tracking Metal Electrodeposition Dynamics from Nucleation and Growth of a Single Atom to Crystalline Nanoparticle

H. E. M. Hussein, R. J. Maurer, H. Amari, J. J. P. Peters, L. Meng, R. Beanland, M. E. Newton, J. V. Macpherson, ACS Nano 12, pp. 7388-7396 (2018)

"Identical Location Scanning Transmission Electron Microscopy and Density Functional Theory calculations give the first account of electrochemically-driven gold deposition with single-atom resolution."