Ultrafast time-resolved vibrational spectroscopies of carotenoids in photosynthesis

Abstract

This review discusses the application of time-resolved vibrational spectroscopies to the studies of carotenoids in photosynthesis. The focus is on the ultrafast time regime and the study of photophysics and photochemistry of carotenoids by femtosecond time-resolved stimulated Raman and four-wave mixing spectroscopies. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.

Femtosecond Stimulated Raman Spectroscopy

“…in 2002, an enormous amount of work has contributed to our understanding of carotene's unique excited‐state dynamics . Recent reviews on carotenes and biopolyenes have been given by Hashimoto et al . and Buckup et al .…”

Isolation and characterization of (15 Z )-lycopene thermally generated from a natural source

“…D.01) using the Becke-3eLeeeYangeParr (B3LYP) functional and 6-31G(d) basis set including a zero point vibrational energy correction. Prior to the calculation for (all-E)-lycopene, the structures of the conjugated all-E-polyenes, C n H nþ2 (n ¼ 4e22, even number) were optimized at the ground singlet states, and followed by the methylated undecaenes (2Z,4E 16,20,5,7,9,11,13,15,17,19,21,. The structure of HMHU was estimated using initial conformers at 30 intervals of the dihedral angles of the free rotation in a stepwise manner for two ethyl groups, and (all-E)-lycopene was then estimated in the same way.…”

“…Since the middle of the 20th century, a large number of studies have been conducted on lycopene, as well as on other carotenoids such as b-carotene and lutein, in order to elucidate their structures, physicochemical properties, biological functions, and biosynthetic mechanisms [3e5]. Recent trends in carotenoid research involve the examination of photophysical and photochemical properties using femto-to picosecond time-resolved spectroscopy [6,7], the biosynthesis of novel carotenoids by evolving metabolic pathways [8], and potential applications in human health and nutrition [9].…”

Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

“…TG probes the sum of the absorptive and dispersive part of the induced third order signal, while pump-probe selects only the absorptive part, meaning that the retrieved time constants cannot be directly compared to pump-probe measurements. 48,49 Vibrational dynamics will however yield similar frequencies between the two techniques (see, e.g., vibrational dynamics in β-carotene investigated by pump-probe 18,50 and by TG 51,52 ). The vibrational response manifests as an oscillatory signal, superimposed on a slowly varying background.…”