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    Comparative performance of different hyperbolic cosine functions and generalized B functions basis sets for atomic systems
    (Iop Publishing Ltd, 2022) Coskun, M.; Erturk, M.
    Recently, we reported a new set of Bessel type functions, which include the radial part of generalized Bessel functions r(n-1)e(-zeta r mu) for LCAO calculations of atomic systems. In this study, to achieve further improvement of the performance of generalized Bessel type basis sets in the Hartree-Fock-Roothaan calculations, different hyperbolic cosine functions inserted into the radial part of those generalized Bessel functions. For this purpose, three different generalized hyperbolic cosine functions have been used to construct the generalized Bessel type hyperbolic cosine basis sets. The accuracies of generalized Bessel type hyperbolic cosine functions within the minimal basis sets approach are compared to show their superiority to conventional approaches those in the literature. The performance of the presented basis functions is also compared to the numerical Hartree-Fock results. Our virial ratios are in good agreement to within 8-digits of the -2. It is shown that the results obtained by the new basis sets surpass the quality and accuracy of existing Bessel type basis sets.
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    Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses
    (Elsevier Sci Ltd, 2012) Harmens, H.; Ilyin, I.; Mills, G.; Aboal, J. R.; Alber, R.; Blum, O.; Coskun, M.
    Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP grids. Correlations frequently improved when only data for EMEP grids with at least three moss sampling sites per grid were included. It was concluded that spatial patterns and temporal trends agree reasonably well between lead and cadmium concentrations in mosses and modelled atmospheric deposition. (C) 2012 Elsevier Ltd. All rights reserved.
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    Double hyperbolic cosine basis sets for LCAO calculations
    (Taylor & Francis Ltd, 2022) Coskun, M.; Erturk, M.
    Recently, we reported a new set of hyperbolic cosine type basis sets, which include the radial part of exponential type functions. In this study, it is show that the double hyperbolic cosine basis sets with non-integer Slater type orbitals give extremely accurate results, with the accuracy superior to that of the previous similar calculations. Total energy differences and comparison between double hyperbolic cosine and other similar basis sets suggested in literature are presented. Using double hyperbolic cosine orbitals, combined Hartree-Fock-Roothaan calculations have been carried out on the ground states of atoms and their ions within the minimal basis sets framework to compare the performance of the basis sets. The basis sets achieved the accuracy far beyond the double-zeta quality. Proposed basis sets can also play an effective role in ion-atom collisions problems and semi-empirical methods.
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    Revitalization of urban ecosystems through vascular plants: preliminary results from the BSEC-PDF project
    (Ist Chimica Agraria, 2011) Gorelova, S. V.; Frontasyeva, M. V.; Yurukova, L.; Coskun, M.; Pantelica, A.; Saitanis, C. J.; Tomasevic, M.
    Passive biomonitoring with plants, in urban environment, is of significant practical value in assessing exposure and human health risks caused by various technogenic pollution impacts. In order to select plant species able to accumulate the anthropogenically emitted heavy metals (HM) and toxic elements in excessive amounts, being tolerant to them, an assessment of the accumulation efficiency of several urban tree species was carried out in six European cities and towns: Sofia (Bulgaria), Athens (Greece), Bucharest (Romania), Tula (Russia), Belgrade (Serbia), and Canakkale (Turkey). The leaves of the selected tree species were collected in summer 2009 and subjected to multi-elements analysis by means of several analytical techniques: ICP-OES, AAS, PIXE, and XRF. The preliminary results of the analysis suggest that the leaves of the species Aesculus hippocastanum, Acer platanoides Populus nigra, and Tilia cordata can be used as accumulators of a number of elements originated from the technogenic pollution: Populus nigra: Mn, Fe, Ni, Zn, Cd, and Pb; Acer platanoides: Mn and Fe; Aesculus hippocastanum: Ni, Cu, As, and Pb; cordata: Al, Fe, and Cu, and Betula pendula: Mn, Ni, Zn, Cd, and Pb.