The 1(2)B(2), 1(2)B(1), 1(2)A(1), 1(2)A(2), and 3(2)A' (2(2)B(2)) states of the CH2Cl2+ ion were studied using the CASPT2 and CASSCF methods. For the first four states, adiabatic excitation energy (TO) calculations support the experimental energy ordering and the CASPT2 calculations produced accurate To values. The CASSCF calculations produced a large imaginary frequency for 2(2)B(2) and predicted a C-s(3(2)A') minimum-energy structure. The CASPT2 calculations indicate that the 3(2)A' state is 0.22 eV lower in energy than 2(2)B(2), and produced a To value for 3(2)A' identical to the experimental value. We suggest that the third band in the PE spectrum is assigned to 3(2)A'. Potential energy curves for Cl-loss dissociation from the 1(2)B(2), 1(2)B(1), 1(2)A(1), and 1(2)A(2) states were calculated at the CASPT2//CASSCF level. (c) 2006 Elsevier B.V. All rights reserved.