Abstract
We present in this paper Stark shifts as a function of temperature for 20 spectral lines of Ar II belonging to 4p - 4d transition array. Calculations are made using semiclassical perturbation approach in impact approximation. Atomic data used in this calculation are carried out using Hartree-Fock method with relativistic corrections. Singly charged argon (Ar II) spectral lines are observed in many astrophysical plasmas. Ar II spectral lines are also important for laboratory plasmas and laser physics and technology.