[ 1] L. Serrano-Andrés, Theoretical Study of the Electronic Spectra of Organic Systems, PhD thesis, University of Valencia, Dept. Química Física, Dr. Moliner 50, Burjassot,E-46100 Valencia, Spain, 1994.

[ 2] L. Serrano-Andrés, M. Merchán, M. Fülscher, and B. O. Roos, A theoretical study of the electronic spectrum of thiophene, Chem. Phys. Letters, 211:125, 1993.

[ 3] B. O. Roos, K. Andersson, M. P. Fülscher, P.-Å. Malmqvist, L. Serrano-Andrés, K. Pierloot, and M. Merchán, Multiconfigurational perturbation theory: Applications in electronic spectroscopy. In I. Prigogine and S. A. Rice, editors, Advances in Chemical Physics: New Methods in Computational Quantum Mechanics, Vol. XCIII:219. John Wiley & Sons, New York, 1996.

[ 4] K. Kaufmann, W. Baumeister, and M. Jungen, J. Phys. B: At. Mol. Opt. Phys., 22:2223, 1989.

[ 5] M. P. Fülscher and B. O. Roos, The excited states of pyrazine: A basis set study, Theor. Chim. Acta, 87:403, 1994.

[ 6] K. Andersson, P.-Å. Malmqvist, B. O. Roos, A. J. Sadlej, and K. Wolinski, Second-order perturbation theory with a CASSCF reference function, J. Phys. Chem., 94:5483, 1990.

[ 7] K. Andersson, P.-Å. Malmqvist, and B. O. Roos, Second-order perturbation theory with a complete active space self-consistent field reference function, J. Chem. Phys., 96:1218, 1992.

[ 8] K. Andersson, Multiconfigurational Perturbation Theory, PhD thesis, University of Lund, Theor. Chemistry, Chem. Center, P.O.B. 124,S-221 00 Lund, Sweden, 1992.

[ 9] B. O. Roos and K. Andersson, Multiconfigurational perturbation theory with level shift -- the Cr₂ potential revisited, Chem. Phys. Letters, 245:215, 1995.

[10] B. O. Roos, K. Andersson, M. P. Fülscher, P.-Å. Malmqvist, L. Serrano-Andrés, K. Pierloot, and M. Merchán, Multiconfigurational perturbation theory: Applications in electronic spectroscopy, In I. Prigogine and S. A. Rice, editors, Advances in Chemical Physics: New Methods in Computational Quantum Mechanics, Vol. XCIII:219. John Wiley & Sons, New York, 1996.

[11] K. Andersson and B. O. Roos, Excitation energies in the nickel atom studied with the complete active space SCF method and second-order perturbation theory, Chem. Phys. Letters, 191:507, 1992.

[12] B. O. Roos, K. Andersson, M. P. Fülscher, L. Serrano-Andrés, K. Pierloot, M. Merchán, and V. Molina, Applications of level shift corrected perturbation theory in electronic spectroscopy, J. Mol. Struct. Theochem, 388:257, 1996.

[13] J. Finley, P.-Å. Malmqvist, B. O. Roos, and L. Serrano-Andrés, The multi-state CASPT2 method, Chem. Phys. Letters, 288:299-306, 1998.

[14] L. Serrano-Andrés, M. Merchán, I. Nebot-Gil, R. Lindh, and B. O. Roos, Towards an accurate molecular orbital theory for excited states: Ethene, butadiene, and hexatriene, J. Chem. Phys., 98:3151, 1993.

[15] M. P. Fülscher, L. Serrano-Andrés, and B. O. Roos, A theoretical study of the electronic spectra of adenine and guanine, J. Am. Chem. Soc., submitted, 1997.

[16] L. Serrano-Andrés and M. P. Fülscher, Theoretical study of the electronic spectroscopy of peptides. 1. The peptidic bond: Primary, secondary, and tertiary amides, J. Am. Chem. Soc., 118:12190, 1996.

[17] M. Merchán, E. Ortí, and B. O. Roos, Theoretical determination of the electronic spectrum of free base of porphin, Chem. Phys. Letters, 226:27, 1994.

[18] L. Serrano-Andrés and B. O. Roos, A theoretical study of the indigoid dyes and their chromophore, Chem. Eur. J., 3:717, 1997.

[19] K. Pierloot, E. Van Praet, L. G. Vanquickenborne, and B. O. Roos, Systematic ab initio study of the ligand field spectra of hexacyanometalate complexes, J. Phys. Chem., 97:12220, 1993.

[20] K. Pierloot, J. O. A. De Kerpel, U. Ryde, and B. O. Roos, A theoretical study of the electronic spectrum of plastocyanin, J. Am. Chem. Soc., 119:218, 1997.

[21] K. Pierloot, E. Tsokos, and B. O. Roos, 3p-3d intershell correlation effects in transition metal ions, Chem. Phys. Letters, 214:583, 1993.

[22] K. Andersson, Different forms of the zeroth-order Hamiltonian in second-order theory with a complete active space self-consistent field reference function, Theor. Chim. Acta, 91:31, 1995.

[23] M. Merchán and R. González-Luque, Ab Initio study on the low-lying excited states of retinal, J. Chem. Phys., 106:1112, 1997.

[24] L. Serrano-Andrés, M. Merchán, B. O. Roos, and R. Lindh, Theoretical study of the internal charge transfer in aminobenzonitriles, J. Am. Chem. Soc., 117:3189, 1995.

[25] M. Merchán, R. Pou-Amérigo, and B. O. Roos, A theoretical study of the dissociation energy of Ni₂⁺. A case of broken symmetry, Chem. Phys. Letters, 252:405, 1996.

[26] M. P. Fülscher, S. Matzinger, and B. Bally, Excited states in polyene radical cations. An ab initio theoretical study, Chem. Phys. Letters, 236:167, 1995.

[27] M. Rubio, M. Merchán, E. Ortí, and B. O. Roos, Theoretical study of the electronic spectra of the biphenyl cation and anion, J. Phys. Chem., 99:14980, 1995.