Ab Initio
A latin term, meaning "from the beginning" or "from first principles," which in terms of nanotechnology simulations refers to the calculation of forces using fundamental quantum mechanic principles, without any reliance on empirical data. Simulation results are based on solutions of Schroedinger's Equation and the wavefunctions used.
In practice, strict ab initio calculations require too much computing power to be practical for anything but a small number of nuclei and electrons. Instead, various approximations are made to simplify the calculations of larger systems, such as Density Functional Theory.
