Ground and excited state polarizabilities and dipole transition propertiesof benzene from coupled cluster response theory

The electronic properties and transition properties have been investigated for the lowest singlet electronic states of benzene using coupled cluster r esponse theory. The polarizabilities have been calculated for the ground st ate and the 1(1)B(2u), 1(1)B(1u) 1(1)E(1u) and 2(1)E(1u) excited states. Th e dipole allowed transitions out of these states have also been calculated and discussed in the context of the calculated polarizabilities. Oscillator strengths and the second electronic moments of the charge distributions ha ve been used to characterize and identify qualitative features of the indiv idual states. The performance of coupled cluster singles (CCS), the recentl y proposed CC2 model, and coupled cluster singles and doubles (CCSD) is com pared. It is demonstrated that the choice of basis set and electronic struc ture model can dramatically effect the calculated transition properties and electronic properties. An interesting disagreement with previous theoretic al studies has been found in the characterization of the qualitative featur es of the 1(1)E(1u) and 2(1)E(1u) states. (C) 1999 Elsevier Science B.V. Al l rights reserved.