Electronic and positron charge densities and band structures of Ga0.5Al0.5N using the empirical pseudopotential method (EPM) are investigated. For the ternary alloy Ga1-xAlxN, the virtual crystal approximation (VCA) is coupled with the pseudopotential method. The energies along Γ , X and L of Ga1-xAlxN alloy as a function of the mole fraction are calculated. Angular correlation of positron annihilation radiation (ACPAR) along different crystallographic directions in Ga0.5Al0.5N is calculated. Other quantities such as ionicity character and bulk modulus by means of recent models [1, 2] with respect to the mole fraction are discussed.
 Y. Al-Douri, H. Abid, A. Zaoui and H. Aourag, Physica B 301, 295, 2001.
 Y. Al-Douri, H. Abid and H. Aourag, Physica B 305, 186, 2001.