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Solving the electronic Schrodinger equation for changing nuclear coordinates provides access to the Born-Oppenheimer potential energy surface. This surface is the key starting point for almost all theoretical studies of chemical processes in electronic ground and excited states (including molecular structure prediction, reaction mechanism elucidation, molecular property calculations, quantum and molecular dynamics). Electronic structure models aim at a sufficiently accurate approaximation of this surface. They have therefore become a cornerstone of theoretical and computational chemistry, molecular physics, and materials science. In this work, we elaborate on general features of approximate electronic structure models such as accuracy, transferability, and general applicability in order to arrive at a perspective for future developments, of which a vanguard has already arrived. Our quintessential proposition is that meaningful quantum mechanical predictions for chemical phenomena require system-specific uncertainty information for each and every electronic structure calculation, if objective conclusions shall be drawn with confidence.
We investigate how different chemical environment influences magnetic properties of terbium(III) (Tb)-based single-molecule magnets (SMMs), using first-principles relativistic multireference methods. Recent experiments showed that Tb-based SMMs can h
We investigate the use of optimized correlation consistent gaussian basis sets for the study of insulating solids with auxiliary-field quantum Monte Carlo (AFQMC). The exponents of the basis set are optimized through the minimization of the second or
We explore the extended Koopmans theorem (EKT) within the phaseless auxiliary-field quantum Monte Carlo (AFQMC) method. The EKT allows for the direct calculation of electron addition and removal spectral functions using reduced density matrices of th
We check the ab initio GW approximation and Bethe-Salpeter equation (BSE) many-body methodology against the exact solution benchmark of the hydrogen molecule H$_2$ ground state and excitation spectrum, and in comparison with the configuration interac
A room-temperature skyrmion-hosting compound Co$_8$Zn$_8$Mn$_4$ has been examined by means of soft X-ray absorption spectroscopy, resonant small-angle scattering and extended reference holography. An element-selective study was performed by exciting