# Main content

# Latest Preprints

### Automated Selection of Active Orbital Spaces

Christopher J. Stein, Markus Reiher. One of the key challenges of quantum-chemical multi-configuration methods is the necessity to manually select orbitals for the active space. This selection requires...

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### Spin-adapted Matrix Product States and Operators

Sebastian Keller, Markus Reiher. Matrix product states (MPSs) and matrix product operators (MPOs) allow an alternative formulation of the density matrix renormalization group algorithm introduced by White. Here, we describe...

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### New Approaches for ab initio Calculations of Molecules with Strong Electron Correlation

Stefan Knecht, Erik Donovan Hedegård, Sebastian Keller, Arseny Kovyrshin, Yingjin Ma, Andrea Muolo, Christopher J. Stein, Markus Reiher. Reliable quantum chemical methods for the description of molecules with dense-lying frontier orbitals are needed in the context of many chemical compounds and reactions. Here, we review developments...

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### Accelerating Wave Function Convergence in Interactive Quantum Chemical Reactivity Studies

Adrian H. Mühlbach, Alain C. Vaucher, Markus Reiher. The inherently high computational cost of iterative self-consistent-field (SCF) methods proves to be a critical issue delaying visual and haptic feedback in real-time quantum chemistry. In this work, we introduce...

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### Real-time feedback from iterative electronic structure calculations

Alain C. Vaucher, Moritz P. Haag, Markus Reiher. Real-time feedback from iterative electronic structure calculations requires to mediate between the inherently unpredictable execution times of the iterative algorithm employed and the necessity to provide data in fixed and short time intervals for real-time rendering. We introduce the concept...

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