The energies and rates of photons emitted during the radiative decay of highly charged ions are promising tools to test the sensitivity of correlation and relativistic higher order corrections. In this talk, the effects of configuration mixing and the radial orbitals used in the evaluation of structure parameters of some Li-like and He-like ions will be discussed. The inter-complex and intra-complex correlations show abrupt changes on the radiative decay of the fine structure states of some Li-like configurations in certain Z region. The relaxed and frozen orbitals are seen to have significant influence on the intensities of the X-ray photons emitted from the doubly excited states of He-like ions. These effects will be high lighted in this talk.