The 1-2 (2) Pi(1/2), 1-2 (2) Pi(3/2), and 1-3 (2) Sigma(1/2)(+) states of GaAr and the 1 (1) Sigma(+) and 1 (3) Sigma(-) states of GaAr+ are calculated by ab initio methods. Spectroscopic properties for these states are compared with experimental data, and the existence of potential barrier for the Rydberg (2) Sigma(1/2) states is explained. We have also proved the nonbonding character of the 1 (2) Pi(1/2)(X) State of GaAr. The bond energy of the doubly excited 1 (3) Sigma(-) state, 12 557 cm-l, is much larger than that of the ground state (X (1) Sigma(-)) of GaAr+, 584 cm(-1), which in turn is more strongly bound than the neutral species (70 cm(-1) for the ground state, 340 cm(-1) for the 2 (2) Pi(3/2) state). The nonbonding character of the X (2) Pi(1/2) State of GaAr can be attributed to the spin-orbit interaction. Transition properties between these states are also calculated.