Assignment on the X, A, B, C, and D States of the C6H5Br+ Cation Based on High-Level Calculations

Geometries, frequencies, and energies of the 1(2)B(1), 1(2)A(2), 1(2)B(2), 2(2)B(1), 2(2)B(2), and 1(2)A(1), of the C6H5Br+ ion were calculated by using CASSCF and CASPT2 methods in conjunction with an ANO-RCC basis. The CASPT2//CASSCF adiabatic excitation energies and CASPT2 relative energies for the six states are in good agreement with experiment. The X, A, B, C, and D electronic states of the C6H5Br+ ion were assigned to be (XB1)-B-2, A(2)A(2), (BB2)-B-2, (CB1)-B-2, and (DB2)-B-2 based on the CASSCF and CASPT2 calculations. The assignment on the D state of the C6H5Br+ ion is different from the previously published works. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 110: 2683-2688, 2010