AbstractsTriplet energy levels and triplet-triplet transition in benzene have been calculated semi-empirically by considering CI up to and including doubly excited configurations and using various values of the core resonance and electron repulsion integrals. The usual method of calibrating j3 (core resonance integral) from one of the observed transitions in the semi-empirical methods is critically examined with respect to the triplet levels of this molecule. Semi-empirical parameters are found to have a pronounced effect on the energy of the triplets and the triplet-triplet transitions; but the intensities of such transitions are quite insensitive to the choice of such parameters.Numerical results show several 3B,, + 3E,, transitions of various intensities. Out of these, the transitions which correspond energetically to the observed triplet-triplet bands are found to have low intensity. Some strong triplet-triplet bands are predicted in the far ultra violet region.On a calcult des niveaux d'tnergies de triplets et des transitions triplet-triplet pour le benzhe avec des mtthodes semi-empiriques. Les configurations deux fois excittes ont ttk inclues et des valeurs difftrentes des inttgrales de rtsonance et de rkpulsion ont t t t essaytes. La mtthode ordinaire pour calibrer j3 de l'une des transitions observh a t t t examinke critiquement par rapport aux niveaux triplets de la moltcule. L'hergie des triplets et les difftrences d'tnergie sont t r h sensibles aux choix des param&res, ce qui n'est pas le cas pour les intensit& des transitions.Les rtsultats indiquent plusieurs transitions 3 4 , --+ 3E2, d'intensites difftrentes. Parmi celles-ci, les transitions qui correspondent du point de vue de l'tnergie aux bandes observtes, ont une intensitt faible. Quelques bandes fortes dans la rtgion ultraviolette lointaines sont prtdites.