Artificial Bee Colony Optimization of Capping Potentials for Hybrid Quantum Mechanical/Molecular Mechanical Calculations

摘要

We present an algorithmic extension of a numerical optimization scheme for analytic capping potentials for use in mixedquantum-classical (quantum mechanical/molecular mechanical, QM/MM) ab initio calculations. Our goal is to minimize bond-cleavage-induced perturbations in the electronic structure, measured by means of a suitable penalty functional. Theoptimization algorithm-a variant of the artificial bee colony (ABC) algorithm, which relies on swarm intelligence-couplesdeterministic (downhill gradient) and stochastic elements to avoid local minimum trapping. The ABC algorithm outperforms theconventional downhill gradient approach, if the penalty hypersurface exhibits wiggles that prevent a straight minimizationpathway. We characterize the optimized capping potentials by computing NMR chemical shifts. This approach will increase theaccuracy of QM/MM calculations of complex biomolecules.