Studies of Higher Triplet Exciton Bands through T-T Absorption in Naphthalene Single Crystal

Abstract

Two T - T transitions in naphthalene crystals have been identified: one with a series f vibronic progressive absorption bands between 3500 A and 4500 A is assigned as the 3 B 1 g - ← 3 B 2 u + transition, and the other with a series of absorption bands between 4500 A and 6000 A is assigned as the 3 A 1 g + ← 3 B 2 u + transition. The shape of the absorption band for the former transition has been studied between 20 K and room temperature, with the result that the shape has no temperature dependence above 80 K while the shape and the polarization change at lower temperatures. The absorption is concluded to be due to a band-to-band transition and the width of the 3 B 1 g - exciton band is determined to be 1050 cm 1 .