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1Author    P. Kierzkowski, B. Pranszke, A. Kowalski, M. MenzingerRequires cookie*
 Title    Electronic Energy Partitioning in the Reactions of Metastable Mg*( 3 Pj) Atoms with F 2 , Cl 2 , Br 2 ,1 2 , IC1, IBr  
 Abstract    Chemiluminescent reactions of metastable Mg*(3 Pj) atoms with F 2 , Cl 2 , Br 2 , I 2 , IC1, IBr molecules were studied in a beam-gas experiment. For all homonuclear targets the MgX(A 2 FI -X 2 X +) emission was observed, but for IC1 and IBr reactants the Mgl(A-X) emission was absent and only MgCl(A-X) or MgBr(A-X) spectra were found. In addition, for the I 2 , IBr, IC1, Br 2 reactions, broad pseudocontinua extend from above 400 nm into the infrared. These pseudocontinua are ten-tatively attributed to the Mgl, MgBr (B' 2 Z + -X 2 Z +) transition. The total attenuation cross sections, chemiluminescence cross sections and quantum yields were measured. The quantum yields are all below 5%. The results are analyzed using information theory. The low yields for the Mg* + F 2 system are explained by a barrier in the entrance channel. For other reactions the low yields are most probably caused by predissociation of the MgX*(A 2 n) products. 
  Reference    Z. Naturforsch. 55a, 433—140 (2000); received November 26 1999 
  Published    2000 
  Keywords    Chemiluminescence, Energy Transfer, Atomic Collisions, Molecular Collisions, Luminescence 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0433.pdf 
 Identifier    ZNA-2000-55a-0433 
 Volume    55 
2Author    M., S. W.Requires cookie*
 Title    Efficiency of Photosubstitution of Arenetricarbonylchromium(O) Complexes  
 Abstract    The quantum efficiency of the formation of (arene)Cr(CO)2(pyridine) (arene = benzene, mesitylene) is reported as a function of the irradiation wavelength of (arene)Cr(CO)3 and as a function of pyridine concentration. The quantum efficiency is independent of pyridine concentration in the range 0.008-0.17 M. The quantum efficiency is 0.72 ± 0.07 upon 313, 366, or 436 nm irradiation. The (arene)Cr(CO)3 complexes are found to quench triplet excited benzil at a diffusion controlled rate and the quenching is accompanied by reaction of the (arene)Cr(CO)3. The reaction product which presumably arises from CO release is the same as that obtained from direct irradiation of (arene)Cr(CO)3 in the presence of benzil. However, the triplet sensitized reaction occurs with a quantum efficiency of only 0.15 ± 0 .0 5 in contrast to the high substitution efficiency (0.72 ±0.07) of (arene)Cr(CO)3 upon direct irradiation. 
  Reference    (Z. Naturforsch. 30b, 254—258 [1975]; received May 10 1974) 
  Published    1975 
  Keywords    Photosubstitution, Metal Carbonyl, Energy Transfer, Photodissociation 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0254.pdf 
 Identifier    ZNB-1975-30b-0254 
 Volume    30 
3Author    Friedrich MönkehausRequires cookie*
 Abstract    /-Phages with different amounts of BU in their DNA-strands were irradiated with long wave­ length UV light (302/313 nm) and short wavelength UV-light (254 nm) in the presence and ab­ sence of cysteamine. It was found that the dose reduction factor is dependent on the percentage BU-substitution only after irradiation with UV-light of 254 nm, not after long wavelength UV-irradiation. Furthermore, the inactivation cross section is proportional to the BU-content of the D N A after irradiation with long and with short wavelength UV-light in the presence of cysteamine. The results lead to the conclusion that the presence of cysteamine inhibits energy transfer pro­ cesses which occur after irradiation with UV-light of 254 nm in the absence of cysteamine. Einfluß von Cysteamin auf die UV-Empnndlichkeit von X-Phagen mit variablem Bromuracil-Gehalt I. Einleitung 
  Reference    (Z. Naturforsch. 29c, 286 [1974]; eingegangen am 14. Dezember 1973) 
  Published    1974 
  Keywords    Cysteamine, UV-Sensitivity, A-Phages, Bromouracil, Energy-transfer 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0286.pdf 
 Identifier    ZNC-1974-29c-0286 
 Volume    29 
4Author    Friedrich MönkehausRequires cookie*
 Title    UV-Empfindlichkeit von >*-Phagen mit variablem Bromuracil-Gehalt UV-Sensitivity of /-Phages with Various BU-Contents  
 Abstract    Heat induction of E. coli CR 34 (Acl857)/A growing in media with variing bromouracil (BU)-contents yielded A-phages with different amounts of BU in their DNA-strands. The percentage sub­ stitution of thymine was determined by buoyant density measurements in a CsCl-density gradient. After irradiation of the phages with long wavelength UV (302/313 nm) and short wavelength UV (254 nm) the sensitivity (loss of infectivity) was determined as a function of the degree of BU-substitution. It was found that after irradiation with long wavelength UV the cross section is proportional to the percentage BU-substitution, whereas after irradiation with short wavelength UV it is not. The results can be explained by assuming energy transfer from the four DNA-bases to the BU. 
  Reference    (Z. Naturforsch. 29c, 289 [1974]; eingegangen am 14. Dezember 1973/19. Februar 1974) 
  Published    1974 
  Keywords    UV-Sensitivity, A-Phages, Bromouracil, Energy-transfer 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0289.pdf 
 Identifier    ZNC-1974-29c-0289 
 Volume    29 
5Author    H. Heithier, H.-J Galla, H. MöhwaldRequires cookie*
 Title    Fluorescence Spectroscopic and Thermodynamic Studies of Chlorophyll Containing Monolayers and Vesicles. Part I: Mixed Monolayers of Pheophytin A and Lecithin  
 Abstract    Mixed monolayers of pheophytin a and a-L-dimyristoyl lecithin (DML) are investigated on the water surface. The studies gain their special value from the simultaneous measurement of surface pressure and fluorescence intensity as a function of the covered area per molecule. A phase separation in the liquid state of the monolayer is established. Phase 1 exists almost exclusively of pheophytin molecules. Phase 2 exists essentially of D M L domains solubilizing pheo­ phytin in a concentration of 15 mol%. During the D M L main transition the pheophytin solubility decreases to about 2 mol%, the excess pheophytin being precipitated within the surface layer. During the pheophytin main transition an ordered structure below the surface layer is formed. A stabilizing interaction between the pheophytin domains and their environment is observed and discussed. A sharp fluorescence change at a pressure below 0.5 dyn/cm indicates another phase transition. It very probably involves an unwrapping of pheophytin from water molecules. 
  Reference    Z. Naturforsch. 33c, 382 (1978); received March 15/April 3 1978 
  Published    1978 
  Keywords    Monolayers, Chlorophyll, Energy Transfer, Fluorescence Spectroscopy, Phase Transitions 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0382.pdf 
 Identifier    ZNC-1978-33c-0382 
 Volume    33 
6Author    S. Achio, M. Iyairi, N. Th, H. SchatzRequires cookie*
 Title    Oxygen-Evolving Extracts from a Thermophilic Cyanobacterium Synechococcus sp  
 Abstract    Spheroplast membranes o f a thermophilic cyanobacterium Synechococcus sp. have been treated with the detergent lauryldim ethylam ine oxide (LD A O). The resulting extracts show (1) light-induced 0 2 evolution with artificial electron acceptors, (2) four-fold enhancement o f the 0 2 evolution relative to chlorophyll, (3) parallel increase o f both the molar ratios o f PS 2/C hl and cyt b559/C hl in the extract, (4) dissociation o f the auxiliary pigm ent phycocyanin upon treatment with LDAO, but still tight association o f allophycocyanin to the photosystem 2 preparation. 
  Reference    Z. Naturforsch. 38c, 44 (1983); received July 2/Septem ber 13 1982 
  Published    1983 
  Keywords    Cyanobacteria, Oxygen Evolution, Photosystem 2, Allophycocyanin, Energy Transfer 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0044.pdf 
 Identifier    ZNC-1983-38c-0044 
 Volume    38 
7Author    S. S. BrodyRequires cookie*
 Title    The Position of Carotene in the D-l/D-2 Sub-Core Complex of Photosystem II  
 Abstract    When the sub-core complex of photosystem II, D1/D2, is irradiated at 436 or 415 nm (absorp-tion by chlorophyll and pheophytin and ß-carotene) or 540 nm (absorption primarily by pheophy-tin), the low temperature fluorescence spectrum has two maxima, at 685 and 674 nm. This shows the existence of at least two different fluorescent forms of chlorophyll (chlorophyll a and perhaps pheophytin a). When carotene is irradiated at 485 nm (absorption primarily by ß-carotene), only fluorescence at 685 nm is observed: this indicates that carotene is transferring energy to only the long-wavelength form of chlorophyll in the D1/D2 sub-core complex. The band of carotene (at 485 nm) does not appear in the fluorescence excitation spectrum, measured at 674 nm. The position of the carotene molecule relative to each of the fluorescent forms of chlorophyll was determined from the excitation spectra of each of the fluorescence bands. 
  Reference    Z. Naturforsch. 43c, 226—230 (1988); received August 21. 1987/January 11 1988 
  Published    1988 
  Keywords    Photosynthesis Photosystem II, Chlorophyll, Fluorescence, Carotenoids, Energy Transfer 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0226.pdf 
 Identifier    ZNC-1988-43c-0226 
 Volume    43 
8Author    B. Pranszke, P. Kierzkowski, A. KowalskiRequires cookie*
 Title    A Search for Isotope Effects in Chemiluminescent Reactions of Metastable Ca*( 3 Pj, *D 2 ) Atoms with CH 3 I and CD 3 I Molecules  
 Abstract    Chemiluminescent reactions of calcium atoms in the metastable Pj and 'D, states with CH 3 I and CD 3 I were studied in a beam-gas arrangement. Calcium monoiodide spectra associated with transitions from the electronic A IT, B 2 Z + and C 2 n states to the X 2 L + ground state were recorded. Total collision and chemiluminescence cross sections were measured. It was found that isotopic substitution in the methyl group does not change the reaction cross sections and the chemiluminescence spectra. 
  Reference    Z. Naturforsch. 54a, 191—194 (1999); received February 2 1999 
  Published    1999 
  Keywords    Chemiluminescence, Energy Transfer, Atomic Collisions, Molecular Collisions, Isotopic Effect 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0191.pdf 
 Identifier    ZNA-1999-54a-0191 
 Volume    54 
9Author    Heinz-Peter Schuchmann, Heinz Bandmann, Clemens Von SonntagRequires cookie*
 Title    The 185 nm Photolysis of 1,4-Dioxane in the Liquid Phase  
 Abstract    The main products in the 185 nm photolysis of neat 1,4-dioxane are formaldehyde (0 = 0.25), glycol monovinyl ether (0.17), and ethylene (0.15). Some hydrogen (0.04), carbon monoxide (0.01), acetaldehyde (0.03), oxetane (0.04), and bidioxanyl (0.01) are also formed. On N20-saturation, the quantum yields of these products are diminished by about 30%, and N2 (0.59) and hydroxydioxane (0.4) become the main products. They are thought to be formed in the reaction sequence hv dioxane > • dioxane* dioxane* + N20 > • dioxane + N2 + O O + dioxane > • hydroxydioxane In aqueous dioxane, photoionisation is possible due to a greater lowering of the ionisa-tion threshold. In dioxane/water 20:80 the main products are H2 (0.50) and bidioxanyl (0.45), most likely formed in consequence of (dioxane)aq (dioxane)aq + eäq (dioxane)Jq • (dioxane-H)-+ H+ eäq + H+ > H-H-+ dioxane >-H2 + (dioxane-H)-2 (dioxane-H)- • bidioxanyl 
  Reference    Z. Naturforsch. 34b, 327—332 (1979); received October 6 1978 
  Published    1979 
  Keywords    Photolysis, 1, 4-Dioxane, Photoionisation, Energy Transfer, Quantum Yields 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0327.pdf 
 Identifier    ZNB-1979-34b-0327 
 Volume    34 
10Author    Peter Brandt, Sabine Marten, Birgit Müller, Wolfgang WießnerRequires cookie*
 Title    Stadienspezifische Thylakoiddifferenzierung der Endocyanelle Cyanocyta korschikoffiana in der symbiontischen Assoziation mit Cyanophora paradoxa Growth Specific Thylakoid Differentiation of the Endocyanelle Cyanocyta korschikoffiana in the Symbiotic Association with Cyanophora paradoxa  
 Abstract    The thylakoid differentiation in the endosymbiotic cyanelle Cyanocyta korschikoffiana depends on the developmental stage o f the whole symbiotic association Cyanophora-Cyanocyta. D uring culturing under perm anent light the intrinsic or extrinsic location and the am ount o f the chlorophyll-protein complexes and of the phycobilines in the thylakoids change markedly. D uring this m odification o f the thylakoids the reaction centers of phytosystem I and II are more and more protected by other proteins. Moreover the am ount of phycobilisomes increases in relation to the am ount o f the chlorophyll-protein complexes. The energy transfer becomes more and more efficient. All these aspects show the typical behaviour of a mass culture of a free-living blue-green alga and imply th at Cyanocyta korschikoffiana is a symbiotic cyanelle much more than a chloroplast-like organelle. 
  Reference    Z. Naturforsch. 37c, 75—80 (1982); received October 211981 
  Published    1982 
  Keywords    Thylakoid D ifferentiation, Endocyanelles, Cyanophora paradoxa, Energy Transfer, Phycobiline 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0075.pdf 
 Identifier    ZNC-1982-37c-0075 
 Volume    37 
11Author    P. Hefferle, P. Geiselhart, T. Mindl, S. Schneider, W. John, H. ScheerRequires cookie*
 Title    Time-Resolved Polarized Fluorescence of C-Phycocyanin and Its Subunits from Mastigocladus laminosus  
 Abstract    The influence o f aggregation and temperature on the excited state kinetics o f C -phycocyanin from Mastiqocladus laminosus has been studied. Polarized fluorescence decay curves have been recorded using a synchronously pum ped dye laser in conjunction with a synchroscan streak camera. The experimental data for all sam ples can be fit satisfactorily assum ing a biexponential decay law. Fluorescence depolarization tim es have been interpreted in terms o f energy transfer among the different chromophores. The influence o f temperature is only m oderate on the intra­ molecular relaxation, but pronounced on the rates o f energy transfer. Both are dependent on the size o f the aggregate. The biexponential decay o f the a-subunit containing only one Chromo­ phore, indicates the presence o f different subsets o f chrom ophores in these sam ples. The results are discussed in terms o f variations o f the chrom ophore arrangem ents upon temperature induced changes in the protein conformation. 
  Reference    Z. Naturforsch. 39c, 606 (1984); received February 16 1984 
  Published    1984 
  Keywords    Photosynthesis, Biliproteins, Picosecond Spectroscopy, Energy Transfer, Protein D enaturation 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0606.pdf 
 Identifier    ZNC-1984-39c-0606 
 Volume    39 
12Author    S. Schneider, P. Geiselhart, S. Siebzehnrübl, R. Fischer, H. ScheerRequires cookie*
 Title    Energy Transfer within PC Trimers of Mastigocladus laminosus Studied by Picosecond Time-Resolved Transient Absorption Spectroscopy  
 Abstract    The transient absorption recovery induced in phycocyanin trimers by picosecond pulses of variable wavelength (570—620 nm) has been recorded and analyzed by applying a least-squares multi-exponential fit procedure. The results suggest that in native PC trimers the chromophores exhibit a microheterogeneity with the effect that the derived apparent lifetimes are functions of excitation and probing wave-length. It is suggested that, due to strong excitonic coupling between a-84 and ß-84 chromophores, the lifetime of the terminal acceptor state is reduced to about 900 ps; the apparent energy transfer time from chromophore ß-155 to a-84 and ß-84 chromophores varies between 20—50 ps depending on the actual chromophore-protein arrangement (microheterogeneity). 
  Reference    Z. Naturforsch. 43c, 55—62 (1988); received July 2/October 12 1987 
  Published    1988 
  Keywords    Energy Transfer, Phycocyanin Trimer, Excited State Lifetimes, Transient Absorption Recovery 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0055.pdf 
 Identifier    ZNC-1988-43c-0055 
 Volume    43 
13Author    R. Steiner, A. A. Ngerhofer+, H. ScheerRequires cookie*
 Title    The Photosynthetic Apparatus of Ectothiorhodospira halochloris 2. Accessibility of the Membrane Polypeptides to Partial Proteolysis and Antenna Polypeptide Assignments to Specific Chromophores  
 Abstract    E. halochloris thylakoids and spheroplasts were treated with trypsin, thermolysin or proteinase K to determ ine which proteins are exposed at the different m embrane surfaces. B ased on SD S polyacrylamide analysis, all 9 polypeptides are exposed on the cytoplasm ic side. O nly one (28 k D a) is accessible from the periplasmic side. This polypeptide is generally isolated as the H-subunit o f the reaction centers of photosynthetic bacteria, but is in the case o f E. halochloris rather isolated with the antenna (B 800/1020) (Steiner and Scheer, Biochim . Biophys. A cta 807, 278, 1983). Proteolysis is accom panied by a shift of the absorption band at longest w avelengths from 1020 to 960 nm (B 800/960), which upon standing is shifted further to 680 nm ("B " 800/680). The spectral changes are similar to the ones reported earlier for treatm ent with acid, and are also inducible with urea. The correlation o f SD S-P A G E and absorption spectroscopy show s, that the chrom ophores absorbing at 1020 nm are transformed sim ultaneously with the degradation o f the 6.5 kD a (— a) polypeptide. 
  Reference    Z. Naturforsch. 41c, 571 (1986); received January 9 1986 
  Published    1986 
  Keywords    Bacterial Photosynthesis, Ectothiorhodospira, M embrane T opology, A ntenna Polypeptides, F luorescence, Circular D ichroism, Energy Transfer 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0571.pdf 
 Identifier    ZNC-1986-41c-0571 
 Volume    41