8 research outputs found

    Dataset to support : FHI-aims benchmark for BEEF-vdW, vdW-DF2 and mBEEFvdW

    Get PDF
    We have performed a benchmark of the BEEF-vdW, mBEEF-vdW and vdW-DF2 implementations in the all-electron electronic structure code in FHIaims against the S22 benchmark set

    Efficient implementation and performance analysis of the independent electron surface hopping method for dynamics at metal surfaces

    Get PDF
    Independent electron surface hopping (IESH) is a computational algorithm for simulating the mixed quantum-classical molecular dynamics of adsorbate atoms and molecules interacting with metal surfaces. It is capable of modelling the nonadiabatic effects of electron-hole pair excitations on molecular dynamics. Here we present a transparent, reliable, and efficient implementation of IESH, demonstrating its ability to predict scattering and desorption probabilities across a variety of systems, ranging from model Hamiltonians to full dimensional atomistic systems. We further show how the algorithm can be modified to account for the application of an external bias potential, comparing its accuracy to results obtained using the hierarchical quantum master equation. Our results show that IESH is a practical method for modelling coupled electron-nuclear dynamics at metal surfaces, especially for highly energetic scattering events

    Data for Efficient implementation and performance analysis of the Independent Electron Surface Hopping method for dynamics at metal surfaces

    No full text
    Independent electron surface hopping (IESH) is a computational algorithm for simulating the mixed quantum-classical molecular dynamics of adsorbate atoms and molecules interacting with metal surfaces. It is capable of modelling the nonadiabatic effects of electron-hole pair excitations on molecular dynamics. Here we present a transparent, reliable, and efficient implementation of IESH, demonstrating its ability to predict scattering and desorption probabilities across a variety of systems, ranging from model Hamiltonians to full dimensional atomistic systems. We further show how the algorithm can be modified to account for the application of an external bias potential, comparing its accuracy to results obtained using the hierarchical quantum master equation. Our results show that IESH is a practical method for modelling coupled electron-nuclear dynamics at metal surfaces, especially for highly energetic scattering events

    On the optical anisotropy in 2D metal-halide perovskites

    No full text
    Two-dimensional metal-halide perovskites (MHPs) are versatile solution-processed organic/inorganic quantum wells where the structural anisotropy creates profound anisotropy in their electronic and excitonic properties and associated optical constants. We here employ a wholistic framework, based on semiempirical modeling (k·p/effective mass theory calculations) informed by hybrid density functional theory (DFT) and multimodal spectroscopic ellipsometry on (C6H5(CH2)2NH3)2PbI4 films and crystals, that allows us to link the observed optical properties and anisotropy precisely to the underlying physical parameters that shape the electronic structure of a layered MHP. We find substantial frequency-dependent anisotropy in the optical constants and close correspondence between experiment and theory, demonstrating a high degree of in-plane alignment of the two-dimensional planes in both spin-coated thin films and cleaved single crystals made in this study. Hybrid DFT results elucidate the degree to which organic and inorganic frontier orbitals contribute to optical transitions polarized along a particular axis. The combined experimental and theoretical approach enables us to estimate the fundamental electronic bandgap of 2.65–2.68 eV in this prototypical 2D perovskite and to determine the spin–orbit coupling (ΔSO = 1.20 eV) and effective crystal field (δ = −1.36 eV) which break the degeneracy of the frontier conduction band states and determine the exciton fine structure. The methods and results described here afford a better understanding of the connection between structure and induced optical anisotropy in quantum-confined MHPs, an important structure–property relationship for optoelectronic applications and devices
    corecore