Abstract

Polyenes are vital in many photobiological functions such as vision and photosynthesis.^[1] Nature has harnessed polyenes as transducers for converting light into chemical energy by exploiting their ability to undergo photochemical isomerization. Also, their unique electronic structure makes polyenes attractive for potential applications as organic conductors and nonlinear optical materials with large third-order susceptibilities. The knowledge of the electronic structure and coupling in the three low energy electronic states - the 1¹ A_g ground state (S₁), 2¹A_g first excited state (S₁), and l¹ B_u second excited state (S₂) - is crucial to understanding the photochemical and electronic properties of polyenes^[1]. Since biological activity of polyenes involves the photoabsorption to the S₂ state and cis-trans isomerization from the S₁ state, we have made a systematic study of the electronic structure and dynamics of the S₁ and S₂ states of short linear polyenes (trienes and tetraenes) under isolated molecular beam conditions and in solution phase.

© 1992 IQEC