Beyond the classical calculations Sample Clauses

Beyond the classical calculations. ‌ Molecular dynamics at the classical and first-principles levels have been introduced and both of these approaches are used widely targeting different domains of problems. With DFT accuracy, the behaviour of materials can be understood and predicted reliably from the interaction due to the electrons, while the classical approaches extends the simulation scale enormously and practically narrows the gap between theoretical description and experimental observations. However, both approaches have limitations when it comes to multi-scale simulations. The classical potentials are less suited to use in new chemical environments beyond the fitting properties and the first-principles methods have limited applicability typically due to its O(N 3) scaling factor, arising from the need to keep wavefunctions orthogonal in the iterative numerical procedures. Linear scaling DFT was recently developed and can accelerate the DFT calculations, but also has limited applications [52, 53]. Beyond the classical description, methodologies such as QM/MM [11], ‘learn-on-the-fly’ (LOTF) MD [12, 54], have been developed and successfully employed into the multi-scale simulations, for instance, to model the fracture, defects or dislocations, to be reviewed in the following sections.