LCAO-MO-SCF-CI semi-empirical ?-electron calculations on heteroaromatic systems part III. Azines

MRINDO/S-CI calculation of the electronic spectra of azines

“…In the present investigation, the electronic spectra of vic-triazine, as-triazine, vic-tetrazine, and as-tetrazine have been calculated. Agreement with the results listed by Pukanic et al [14] is good. In addition, we interpret n-p states and Rydberg transitions of these isomers.…”

“…The percentages of the Rydberg character for all these triplet states are zero and hence are not cited in Table 3 for clarity. The ®rst columns of Table 3 contain results listed by Pukanic et al [14]. A comparative list of the singlet p 3 p* transitions in the four azines under the MRINDO/S approximation is provided in Table 4.…”

“…The theoretical values listed by Pukanic et al [14] are given in the ®rst columns. The last columns of Table 2 contain the percentages of Rydberg character of the excited states.…”

“…vic-triazine, astriazine, vic-tetrazine, and as-tetrazine. Pukanic et al [14] considered these isomers but restricted their calculations to p electrons only. They could not interpret n-p states and Rydberg transitions occuring in the spectra of these isomers.…”

“…The geometry for the bond lengths of these azines has been taken from Pukanic et al [14]. Each molecule was taken to be planar and reasonable bond angles were chosen to give the appropriate dimensions.…”