The ground and low-lying excited states of AlAs-, AlAs, AlAs2-, and AlAs2 are studied using DFT and CCSD(T) approximation. AlAs- has a (2)Sigma(-) ground state with a (2)Pi state 1.08 kcal/mol above. AlAs has a (3)Sigma(-) ground state with the lowest (3)Pi and (1)Sigma(-) states at 2.32 and 15.14 kcal/mol, respectively. Adiabatic electron affinity (AEA) of AlAs is 1.91 eV at the CCSD(T) level. AlAs- and AlAs2 have (1)A(1) and B-2(2) ground states, respectively. CCSD(T) predicts the AEA of AlAs, to be 2.07 eV. Electron detachment processes from AlAs- and AlAs2- ground states are presented and discussed. (C) 2002 Published by Elsevier Science B.V.