Laser action and excited state absorption of chlorophyll-a

Leupold, D.; Mory, S.; König, Roland; Hoffmann, P.; Hieke, B.

doi:10.1016/0009-2614(77)80091-2

Cited by 21 publications

(6 citation statements)

References 4 publications

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“…As discussed above, GSB and SE have the same anisotropy after internal conversion. Several measurements15,17,74 including transient absorption and Z-scan spectroscopy have shown that the extinction coefficient of ESA at the Q y peak is less than 5%, making eqn (3) valid for estimating the angle between TDMs (see S5 and Fig. S4d†).…”

Section: Resultsmentioning

confidence: 99%

Vibronic structure of photosynthetic pigments probed by polarized two-dimensional electronic spectroscopy andab initiocalculations

et al. 2019

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Section: Resultsmentioning

confidence: 99%

Vibronic structure of photosynthetic pigments probed by polarized two-dimensional electronic spectroscopy andab initiocalculations

et al. 2019

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“…Researchers now realize that excitation with trains of high-intensity picosecond pulses, or in some cases with high-intensity (> 1013 photons/cm2) single picosecond pulses, can cause multiple excitation effects, which lead to a dramatic intensity dependence of fluorescence quantum efficiencies and lifetimes (1S, 20,39,45, 75, 76, 94, llS). These difficulties, along with the possible effects of stimulated emission (46,69) and pigment heterogeneity (12, 117, l1S), have necessitated a reinterpretation of early measurements of photosynthetic sys tems. However, the intensity dependence of the fluorescence quantum efficiency has been used recently to explore the organization of the photosynthetic units fr om several strains of photosynthetic bacteria (17).…”

Section: Introductionmentioning

confidence: 98%

Picosecond Flash Photolysis in Biology and Biophysics

Holten¹,

Windsor²

1978

Annu. Rev. Biophys. Bioeng.

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Three years ago one of us was asked by a funding agency to dust off his crystal ball and assess the fu ture importance of picosecond studies to chemistry. After a careful "objective" review of what had been accomplished up to then, and trying hard not to appear self-serving, he boldly concluded that a modest increase in the level of fu nding for picosecond instrumental developments appeared to be justified. In the light of what has occurred since then, this recommendation can only be considered cowardly. Almost all application of picosecond techniques in biology and biophysics has taken place in the past 2 or 3 years. Valuable new insights have been gained and in some areas, notably photosynthesis, striking ad vances in understanding have been made. Why? What special magic do picosecond techniques hold for biology? To answer this question we must trace its roots back to chemistry. The vast majority of chemical and biochemical reactions are composed of many elementary steps. The primary steps, which involve energy migration, bond breakage, molecular rearrangements, and charge transfer, all occur in the time range fr om about 10-14 to 10-8 sec. The "slowness" of an overall reaction is usually determined by other considerations, such as steric fa ctors and diffusion of reactants to the site of reaction. Picosecond spectroscopy enables us for the fi rst time to take a look at these primary steps.In this review we fo cus on the new insights that picosecond studies have provided in several important areas of biology. The area that has received the greatest emphasis to date is photosynthesis, which undoubtedly is appropriate, since we are all dependent upon photosynthesis both for our origin and for our continued survival. Picosecond fluorescence studies in both plants and bacteria show that excitation energy migrates fr om the antenna or light-harvesting system to the . reaction center in times that range fr om 10 psec to about I nsec, depending upon 189

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“…The project, starting in the 1970s when lasers first became available as powerful tools for (photosynthesis) research purposes, was very productive. This is illustrated by a number of publications, for example, ''Laser action and excited state absorption of chlorophyll a'' (Leupold et al 1977), ''Low intensity two step absorption of chlorophyll a in vivo'' (Leupold et al 1978), and ''Collective excitation and luminescence of chlorophyll in vivo'' (Leupold et al 1979). For the excellent results emerging from these interdisciplinary efforts, Paul Hoffmann and the associated team of physicists and mathematicians were awarded the highly prestigious Leibniz Prize (Leibniz-Preis) of the Academy of Sciences of the GDR in 1979.…”

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confidence: 99%