Low-Resolution Analysis of the n→π* (3000 A) Absorption Spectrum of s-Triazine

The 3000‐A absorption band of s‐triazine has been examined under low resolution. The long wavelength portion of this band is assigned to the allowed n→π^* promotion ${}^1{A}_2^{\mathrm{\prime \prime }}{\leftarrow }^1{A}_1^{\prime }$ with 0–0 band at 31 574±15 cm^—1. Evidence is presented for the onset of a second n→π^* transition at ∼32 500 cm^—1. The observed sequence of states contradicts previous predictions based on approximate sp² hybridization, and indicates that in the excited states the n orbital has very little s character (∼0.1).