Correlated n 1,3 S states for coulomb three‐body systems

n 1,3 S ( n = 1 − 4) states for atomic three‐body systems are studied with the Angular Correlated Configuration Interaction method. A recently proposed angularly correlated basis set is used to construct, simultaneously and with a single diagonalization, ground and excited states wave functions which: (i) satisfy exactly Kato cusp conditions at the two‐body coalescence points; (ii) involve only linear parameters; (iii) show a fast convergency rate for the energy; and (iv) form an orthogonal set. The efficiency of the method is illustrated by the study a variety of three‐body atomic systems [ m   1 −m   2 −m   3 z   3 + ] with two negatively charged light particles, with diverse masses m   1 −and m   2 − , and a heavy positively charged nucleus m   3 z   3 + . The calculated ground 1 1 S and excited n 1,3 S ( n = 2 − 4) state energies are compared with those given in the literature, when available. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011