Spectroscopic Investigation of the Carotenoid Deoxyperidinin: Direct Observation of the Forbidden S0 ↿S1 Transition

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• 作者：Jordan A. Greco ; Amy M. LaFountain ; Naoto Kinashi ; Tetsuro Shinada ; Kazuhiko Sakaguchi ; Shigeo Katsumura ; Nikki Cecil M. Magdaong ; Dariusz M. Niedzwiedzki ; Robert R. Birge ; Harry A. Frank
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：March 17, 2016
• 年：2016
• 卷：120
• 期：10
• 页码：2731-2744
• 全文大小：857K
• ISSN：1520-5207

文摘

This paper presents a spectroscopic investigation of deoxyperidinin, a synthetic peridinin analogue in which the carbonyl functional group in peridinin was replaced by a nonconjugated methylene group. Steady-state and ultrafast time-resolved absorption and fluorescence spectroscopic experiments are carried out on deoxyperidinin in n-hexane and acetonitrile at room temperature and in 2-methyltetrahydrofuran at 77 K. The spectra of deoxyperidinin have higher vibronic resolution compared to those of peridinin. The higher resolution is due to a substantial reduction in both molecular conformational disorder and inhomogeneous broadening of the spectra of deoxyperidinin compared to peridinin. Features in the steady-state absorption spectrum of deoxyperidinin that are not evident in the spectrum of peridinin are unambiguously assigned to the forbidden S₀ (1¹A_g^–) → S₁ (2¹A_g^–) absorption transition. The characteristics of both the steady-state and time-resolved spectra are interpreted using EOM-CCSD, SAC-CI, and MNDO-PSDCI quantum computational formalisms that provided a theoretical framework for understanding the photophysical properties of the molecules.