Computer modelling is a powerful enterprise for the investigation of matter
at atomic and molecular levels, and has generally been accepted as a supplementary
tool to traditional experimental methods. Its advantages over real experiments are
primarily exemplified by its portability and cost effectiveness. Monte Carlo and
Molecular Dynamics methods are two principal techniques that have gained a great
level of popularity among various computer simulation methods. Numerous
mathematical models, popularly known as Forcefields, have been developed in order to
investigate water computationally. The application of computer simulation methods is
limited by the choice of parameters that define the intra and inter molecular interactions
within the framework of Forcefields. Ab−initio forcefields are expected to overcome
the limitations of other types of water models. Concept of ensemble provides a
theoretical basis for deriving physical properties by significantly reducing number of
particles in a system. Mathematical devices such as Periodic Boundary Conditions
(PBC) bypass the inconsistencies in simulations. Density Functional Theory (DFT) and
Wave Function methods are two important classes of quantum chemical methods for
investigating matter at electronic level. Born−Oppenheimer approximation provides a
fruitful means for separating electronic and nuclear motions, which reduces the
complexity of quantum calculations to a great extent. Hartree−Fock (HF) method is the
most fundamental wave function procedure for calculating the energy of
multi−electronic systems. On the contrary, Density Functional Theory (DFT) is based
on the estimation of electron density, which can be validated by experimental means.
Combined electronic and classical approaches are increasingly becoming popular in the
scientific community.
Keywords: Basis sets, Boltzmann factor, Ensemble, Equilibration, Ergodic,
Forcefield, Initialisation, Molecular dynamics, Periodic boundary, Production,
Quantum mechanics, Shifting function, Switching function.
