The Near Ultraviolet Absorption Spectrum of Toluene Vapor

The experimental work of Savard and the theoretical work of Sponer on the absorption spectrum of toluene vapor is extended. A spectrum of 209 bands was observed with partial resolution of the fine structure. A tentative analysis is given based on ground state frequencies 514, 620, 785, 1003, 1012, 1176, and 1209, which correlate completely with Raman data; on excited state frequencies, 456, 528, 751, 932, 964, and 1186; and on difference frequencies 59 and 178 cm−1. Assuming C2v symmetry, all frequencies below 1300 cm−1 of symmetry class A1 appeared in 1–0 transitions and with one exception in 0–1 transitions. In addition, a vibrational frequency of symmetry class B1, deriving from an εg+ vibration in benzene, appeared strongly both in the ground and excited state.