  Density functional theory (DFT) has emerged as one of the most versatile and
lucrative approaches in electronic structure calculations of many-electron
systems in past four decades. Here we give an account of the development of a
variational DFT method for atoms and molecules \emph{completely} in a Cartesian
grid. The non-relativistic Kohn-Sham equation is solved by using an LCAO-MO
ansatz. Atom-centered localized basis set, electron density, molecular
orbitals, two-body potentials are directly constructed on the grid. We adopt a
Fourier convolution method for classical Coulomb potentials by making an
Ewald-type decomposition technique in terms of short- and long-range
interactions. It produces quite accurate and competitive results for various
properties of interest, such as component energy, total energy, ionization
energy, potential energy curve, atomization energy, etc. Both local and
non-local functionals are employed for pseudopotential as well as full
calculations. While most results are offered in a \emph{uniform} grid, initial
exploratory attempts are made in a \emph{non-uniform} grid, which can
significantly reduce the computational overhead. This offers a practical,
viable alternative to atom-centered grid-based implementations, currently
exploited by the majority of programs available world-wide.
