The S1and T1energy levels of all-transβ-carotene

Abstract
Reflectance spectroscopy of all-transβ-carotene in the zeolite, ZSM-5, allows the forbidden S0→ S1 transition (1 1Ag–→ 2 1Ag–) to be detected; hence the S1 energy level is determined for the first time and an estimate of the T1 energy level made.