Abstract
In recent years, the applications of first-principles density functional theory (DFT) is diversified and expanded in a wide range due to the development of robust algorithms and more powerful computer systems. In general, DFT is used in condensed matter physics, chemistry, material science and biology to predict and interpret the behaviour of complex-system at atomic-scale. Specifically, DFT is widely applied to study the effect of dopants on phase transformation, magnetic and electronic behaviour, spin and charge transport properties, etc. in material science/condensed matter physics; geometrical and electronic structure, dynamics, spectral hyperfine-interaction, excited-state, etc. in chemistry; interactive behaviour, bond formation and breaking, stabilization, etc. in the biological system. Furthermore, the solvation models are used to include a solvent for the accuracy and realistic approach. To study the physical/chemical and biological system with DFT embedded tools such as Gaussian, Vienna Ab initio software package (VASP), Quantum espresso etc., require a basic theoretical understanding of DFT. Therefore, I have summarised DFT including basis set and solvation models for easy understanding in a short time.