The 3100 Å system of s-triazine and the geometry in the excited state

The n, π ^∗ absorption spectra of gaseous s-triazine (C ₃H ₃N ₃) and its deuterated compound have been studied under high resolution. From a partial rotational analysis of the J-structure of one band in each isotope, the molecular structure in the excited state was determined by assuming the CH distance only. The structural parameters obtained are, r _CN = 1.346 Å, ∠CNC = 122°, r _CH ( assumed) = 1.07 Å (assumed) . The CN bond length and ∠CNC increase by 0.008 Å and by about 9° upon excitation, respectively.