The general procedure underlying Hartree-Fock and Kohn-Sham densityfunctional theory calculations consists in optimizing orbitals for aself-consistent solution of the Roothaan-Hall equations in an iterativeprocess. It is often ignored that multiple self-consistent solutions can exist,several of which may correspond to minima of the energy functional. In additionto the difficulty sometimes encountered to converge the calculation to aself-consistent solution, one must ensure that the correct self-consistentsolution was found, typically the one with the lowest electronic energy.Convergence to an unwanted solution is in general not trivial to detect andwill deliver incorrect energy and molecular properties, and accordingly amisleading description of chemical reactivity. Wrong conclusions based onincorrect self-consistent field convergence are particularly cumbersome inautomated calculations met in high-throughput virtual screening, structureoptimizations, ab initio molecular dynamics, and in real-time explorations ofchemical reactivity, where the vast amount of data can hardly be manuallyinspected. Here, we introduce a fast and automated approach to detect and cureincorrect orbital convergence, which is especially suited for electronicstructure calculations on sequences of molecular structures. Our approachconsists of a randomized perturbation of the converged electron density(matrix) intended to push orbital convergence to solutions that correspond toanother stationary point (of potentially lower electronic energy) in thevariational parameter space of an electronic wave function approximation.
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