THEORETICAL-STUDY OF THE ELECTRONIC STATES OF SI2C

The ground state and electronically excited singlet and triplet states of Si2C have been investigated by ab initio calculations. For the ele ctronic ground state, rovibrational energy levels have been evaluated by a variational approach using several different potential energy fun ctions. The equilibrium geometry, the centrifugal distortion constants , and the vibrational levels up to 1500 cm(-1) are given. The best fun ction yielded an electronic barrier to linearity of 859 cm(-1). The ch anges in the K-a level structures of the rovibrational levels caused b y this barrier are predicted to appear between the v(2) = 4 and v(2) = 6 vibrational states. The results are compared with available experim ents and with those of other theoretical studies. The electronically e xcited singlet and triplet states have been characterized by their pot ential energy functions. The avoided crossings and conical intersectio ns in the excited states have been located and their influence on the electronic spectra is discussed.