  An atom placed inside a cavity of finite dimension offers many interesting
features, and thus has been a topic of great current activity. This work
proposes a density functional approach to pursue both ground and excited states
of a multi-electron atom under a spherically impenetrable enclosure. The radial
Kohn-Sham (KS) equation has been solved by invoking a physically motivated
work-function-based exchange potential, which offers near-Hartree-Fock-quality
results. Accurate numerical eigenfunctions and eigenvalues are obtained through
a generalized pseudospectral method (GPS) fulfilling the Dirichlet boundary
condition. Two correlation functionals, \emph{viz.,} (i) simple, parametrized
local Wigner-type, and (ii) gradient- and Laplacian-dependent non-local
Lee-Yang-Parr (LYP) functionals are adopted to analyze the electron correlation
effects. Preliminary exploratory results are offered for ground states of
He-isoelectronic series ($Z=2-4$), as well as Li and Be atom. Several low-lying
singly excited states of He atom are also reported. These are compared with
available literature results -- which offers excellent agreement. Radial
densities as well as expectation values are also provided. The performance of
correlation energy functionals are discussed critically. In essence, this
presents a simple, accurate scheme for studying atomic systems inside a
\emph{hard} spherical box within the rubric of KS density functional theory.
