White-light continuum probed femtosecond time-resolved absorption spectroscopic measurement of β-carotene under high pressure

• Published in: Chemical physics letters Vol. 532; pp. 47 - 51
• Main Authors: Liu, Wei-Long, Zheng, Zhi-Ren, Zhang, Jian-Ping, Wu, Wen-Zhi, Li, Ai-Hua, Zhang, Wei, Huo, Ming-Ming, Liu, Zhi-Guo, Zhu, Rui-Bin, Zhao, Lian-Cheng, Su, Wen-Hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 12.04.2012
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2012.02.053

With rising pressure, the energy level of S1 state of β-Car descends, whereas its lifetime becomes longer. [Display omitted] ► We established the white-light probed high-pressure transient absorption technique. ► The lifetime of S1 state in β-carotene becomes longer with the rising pressure. ► The energy level of S1 state in β-carotene descends with the rising pressure. ► Solvent viscosity damps the CC stretching vibrations in the S1-to-S0 IC process. ► Microcosmic environment affects the excited state dynamics in carotenoids. We have performed a femtosecond time-resolved absorption spectroscopic experiment of β-carotene in n-hexane solution under high pressure up to ∼1.0GPa. Using white-light continuum in the visible spectral region as probe light, we found that the energy level of S1 state descends, whereas its lifetime becomes longer with the rising pressure. We ascribe this tendency deviating from the energy gap law to the viscosity effects on the CC stretching vibrations, which is fully consistent with the microviscosity theory. This Letter may provide some insights on the light harvesting and photoprotection functions of carotenoids in photosynthetic organisms.