  Within the finite-field Kohn-Sham framework, static electric response
properties of diatomic molecules are presented. The electronic energy, dipole
moment ({\boldmath$\mu$}), static dipole polarizability ({\boldmath$\alpha$})
and first-hyperpolarizability ({\boldmath$\beta$}) are calculated through a
pseudopotential-DFT implementation in Cartesian coordinate grid, developed in
our laboratory earlier. We engage the Labello-Ferreira-Kurtz (LFK) basis set;
while four local and non-local exchange-correlation (LDA, BLYP, PBE and LBVWN)
functionals have been adopted. A detailed analysis of \emph{grid convergence}
and its impact on obtained results, is presented. In each case the
\emph{electric field optimization} was carefully monitored through a recently
prescribed technique. For all three molecules (HCl, HBr, HI) considered, the
agreement of all these quantities with widely successful and popular
atom-centered-grid procedure, is excellent. To assess the efficacy and
feasibility, companion calculations are performed for these on a representative
molecule (HCl) at distorted geometries, far from equilibrium. Wherever
possible, relevant comparison is made with available \emph{all-electron} data
and experimental results. This demonstrates that Cartesian grid provides
accurate, reliable results for such properties of many-electron systems within
pseudopotential representation.
