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In this paper. we employ a diabatic model Hamiltonian based on the DIM (diatomics-in-molecules) and DIIS (diatomics-in-ionic-systems) methods to describe the valence and ion-pair states of the iodine molecule, with the objective of characterizing the influence of Ar and Kr rare gas matrices on the ion-pair states. In particular, we combined this model Hamiltonian with classical simulations to calculate the shifts of the ion-pair state emission spectra due to solvation environment. The computed main emission peaks in Ar and Kr solids appear at 378 and 417 nm, in excellent agreement with the experimental emission peaks of 380 and 418 nm recently observed by Chergui et al. with the identical transition assignments. Our study also shows that these calculated bands correspond to redshifts from the gas phase of 2600 and 5100 cm-1, compared with shifts of 2900 and 4700 cm-1, respectively, observed in experiments, and the equilibrium bond lengths of the D'(2g) state in Ar and Kr extend to 3.70 and 3.75 A compared to the gas-phase value of 3.594 A. consistent with experimental implications. Emission bands originating from the δ(2g) state are also computed, as well as the counterparts of these hands in the visible region and the results are shown to be in reasonable agreement with experiments. We present a detailed study of the ion-pair state symmetry breaking which mixes the symmetrical gas-phase states resulting in charge localization, and the establishment of permanent molecular dipole moments in these solvated ion-pair state molecules due to local distortion of the polarizable matrix. Finally we use our calculations to explore model defect solvation sites in solid Ar which have been proposed as the source of various ambiguous emission bands in experimental spectra. [ABSTRACT FROM AUTHOR]

In this paper we investigate the temperature sensitivity of the photosynthetic process of the benthic diatom Cylindrotheca closterium grown in light-limited turbidostat cultures at two different growth rates. Photosynthesis was measured as the rate of oxygen evolution and as the photosystem II (PSII) electron transport rate (ETR). The photosynthetic efficiency ( α ), as measured by both methods, was rather insensitive to temperature, and decreased significantly only at the extreme temperatures used (5 and 35°C). The maximum PSII quantum efficiency ( F v / F m ) showed a small but significant trend of reduction with increasing temperature. However, the maximum rate of photosynthesis ( P B max and ETR max ) was extremely temperature sensitive. The effect of temperature on the relationship between P B and ETR was limited to the most extreme temperatures investigated; deviations from linearity were most extreme at 5°C and different conversion factors were observed at 5 and 35°C. A short-term change in temperature (10 - 30°C), as might be experienced during emersion on a European tidal flat, will not significantly affect the relationship between P B and ETR. However, care should be taken when using a single conversion factor between P B and ETR at the extremes of the temperature range. We have also shown that algal absorption measurements are important for correct calculation of ETR. The facts that different species seem to have different conversion factors and that changing environmental conditions will affect the absorption capacity and growth rate of the microphytobenthos (MPB) community suggest that it is wise to perform further calibrations of the relationship in the field before use in primary production modelling. Variable fluorescence measurements are quick and non-invasive and, with knowledge of the absorption properties of the MPB community, allow the quantification of photosynthetic parameters across large areas. Hence they are... [ABSTRACT FROM AUTHOR]

The article offers information on the papers which won the 2008 Tyge Christensen Prize. It mentions that the paper by K. Hoef-Emden provides the description of putative biological species in the genus Cryptomonas. It notes that the paper by N. Cassar and E. A. Laws examined parameters which affect the efficiency of phosphoenolpyruvate carboxylase (OPEPCC) and phosphoenolpyruvate carboxykinese (PEPPCK) in the diatom Pheodactylum.

The article announces the joint winners for the Tyge Cgristensen Prize 2007, for the best papers published in the journal in 2006, which are "Toward a Protein Map of the Green Algal Eyespot: Analysis of Eyespot Globule Associated Proteins" by S. Renninger, C.L. Diechmann, and G. Kreimer and "Evolution of the Diatoms: Insights from Fossil, Biological and Molecular Data," by Patricia A. Sims, David G. Mann, and Linda K. Medlin.