Abstract
In this work, fully relativistic multi-configuration Dirac-Hartree-Fock approach for calculating atomic structure parameters has been presented and compared to other approaches such as Hartree-Fock pseudo-Relativistic (HFR) method. As an example of application, results of fully relativistic calculations for the ion Ca XV have been obtained and compared to Hartree-Fock pseudo-relativistic calculations and to NIST database values.This example is important for plasma diagnostic and astrophysical studies because Ca XV atomic data of high accuracy are still very scarce.