Photolysis kinetics by frequency doubled laser emission
| Autor: | Hubertus Staerk |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Materials science
Ruby laser Photodissociation Biophysics Analytical chemistry chemistry.chemical_element Cell Biology Laser Biochemistry law.invention Wavelength Xenon chemistry Structural Biology law Genetics Quantum efficiency Photosynthetic bacteria Absorption (electromagnetic radiation) Molecular Biology |
| Zdroj: | FEBS Letters. (4):287-291 |
| ISSN: | 0014-5793 |
| DOI: | 10.1016/0014-5793(69)80160-2 |
| Popis: | In recent years the use of crystal lasers for the activation of photosynthetic reactions has been developed [ 1,2] and has provided unique experimental data on the cytochrome c-chlorophyll reaction in photosynthetic bacteria over a wide temperature range. The chlorophyll and carotenoids in photosynthetic bacteria and plants absorb laser light with a high quantum efficiency [3]. Thus, only I-10 mJ of ruby laser light is needed to fully activate these systems. Photo lysis of haemoproteinC0 compounds is a much more difficult problem since their absorption coefficients at 694 mn are much lower than that of chlorophyll. A frequency doubling technique has been used in this work to obtain 347 mn radiation, a wavelength at which haemoproteins have higher extinction coefficients. Although the peaks of the Soret bands are in the 400-450 nm region, the absorption at 347 mn is, for carbomnonoxy-haemoglobin, 6 times as great as at the Soret band peak and 800 times as great as at 694 mu. The absorbancy changes caused by the laser photolysis were read in the 400-500 nm region. Among the principal advantages of laser photolysis over the conventional xenon flash technique include the shorter laser flashes at comparable numbers of quanta [4], the greater ease in spectrally separating the exciting and measuring light, the highly specific excitation obtainable with the approximately monochromatic laser light and the ease of operating the Fig. 1. Block diagram of apparatus. BL FD, frequency doubler; hi, front-surface mirror; P, quartz plate; PM, photomultiplier; Q, quartz lens; S, sample; T, tungsten lamp; LC, 18A and 9782, filters. |
| Databáze: | OpenAIRE |
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