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Öğe An improvement on ?(?*)-exponential type orbitals for atoms in standard convention(Taylor & Francis Ltd, 2014) Guseinov, Israfil Isa; Sahin, E.; Erturk, M.The complete orthonormal sets of psi((alpha)*())-exponential type orbitals (psi((alpha)*())-ETOs) in LCAO approximation are investigated for the determination of the optimal values of integer (- < 2) and non-integer * (- < * < 3) by minimising the total energies in atomic calculations. The Hartree-Fock-Roothaan calculations with the use of different values of indices and * are performed within the framework of the minimal basis sets approximation for the ground states of neutral atoms. It is found for non-integer values of * that the efficiency of psi((alpha)*())-ETOs in total energy calculations, electron density, and its derivative and cusp ratio at the nuclei is much better than the other integer values of . It should be noted that the Coulomb-Sturmian and Lambda ETOs are special classes of (())-ETOs for = 1 and = 0, respectively. The performance of psi((alpha)*())-ETOs in atomic energy calculations is also compared to those obtained by using other ETOs such as Slater and B functions. The optimal non-integer values of * are also determined for each atom examined in this work. It is shown that the notably improvement in the efficiency of psi((alpha)*())-ETOs can be obtained by the use of non-integer * values.Öğe Application of combined Hartree-Fock-Roothaan theory to atoms with an arbitrary number of closed and open shells of any symmetry(Springer Wien, 2007) Guseinov, Israfil Isa; Mamedov, B. A.; Ertuerk, M.; Aksu, H.; Sahin, E.The applicability of a combined open-shell Hartree-Fock theory of atomic-molecular and nuclear systems to the states of a single configuration which has the arbitrary symmetry of open shells is explicitly demonstrated by calculations based on the combined Hartree-Fock-Roothaan equations for atoms. As examples of an application of the combined theory using single-zeta Slater-type basis sets, the calculations have been performed for the lowest states of the lowest and excited electronic configurations of carbon and nitrogen atoms containing one-, two- and three-open shells. For the case of single-open shells for carbon and nitrogen atoms, the double-zeta basis-set calculations are also presented. The results of computer calculations for the orbitals, kinetic and total energies, linear combination coefficients and virial ratios are given.Öğe Calculation of negative ions of B, C, N, O and F using noninteger n Slater type orbitals(Chinese Chemical Soc, 2008) Guseinov, Israfil Isa; Ertuerk, M.; Sahin, E.; Aksu, H.; Bagci, A.Combined Hartree-Fock-Roothaan calculations have been performed using noninteger n Slater type orbitals for the ground states of the lowest electron configurations 1s(2)2s(2)2p(n) (2 <= n <= 6) for negative ions of B, C, N, O and F. These results are compared with the corresponding results obtained from the use of integer n Slater type orbitals. All of the nonlinear parameters are fully optimized. The results of calculation of coupling-projection coefficients, orbital and total energies and virial ratios are presented. It is shown that the noninteger n Slater type orbitals, in general, improve the orbital energies.Öğe Generalized B functions applied to atomic calculations(Elsevier, 2020) Erturk, Murat; Sahin, E.During the past years, there has been an increasing interest in the construction of alternative basis sets for electronic systems. .In this work, by the use of generalized exponential functions approach, new efficient exponential type basis sets which include the B functions in the radial part have been constructed. Additional variational flexibility for the radial part of B functions is obtained by replacing the radial variable by r(mu), with mu optimisable. Thus, the new variational parameter mu in generalized B functions greatly improves the quality of atomic orbitals in the LCAO calculations. Results obtained using generalized B function basis sets within the minimal basis framework are compared to the results of the standard B functions basis sets and numerical Hartree-Fock values for atomic systems.Öğe Matter collineation classification of Bianchi type II spacetime(Springer/Plenum Publishers, 2006) Camci, U.; Sahin, E.In this paper we classified the matter collineations (MCs) of Bianchi type II spacetime according to the degenerate and non-degenerate energy-momentum tensor. It is shown that when the energy-momentum tensor is degenerate, most of the cases yield infinite dimensional MCs whereas some cases give finite dimensional Lie algebras in which there are three, four or five MCs. For the non-degenerate matter tensor cases we obtained that the Lie algebra of MCs is finite dimensional, in which the number of MCs are also three, four or five. Furthermore, we discussed the physical implications of the obtained MCs in the case of perfect fluid as source.Öğe Radiation exposure during percutaneous nephrolithotomy; Is there a risk of the patient and the operating team?(Ijrr-Iranian Journal Radiation Res, 2018) Sahin, E.; Kara, C.; Resorlu, B.; Sonmez, M. Giray; Unsal, A.Background: The aim of this study was to calculate the radiation amount exposed during percutaneous nephrolithototomy (PCNL) and to make the urologists and other staff sensitive about the radiation risk they were exposed to. Materials and Methods: We measured the radiation exposure during 114 cases of PCNL performed. Thermoluminescent dosimeters (TLD) were placed between the operation table and the patient at the location of kidney and gonads of patients to measure the radiation exposure of patients. TLD were placed at the head, neck, finger and the legs of the operating surgeon to measure the occupational exposure of the urologist. And also two dosimeters were placed to the inner wall of the operating room and two dosimeters were placed to the hall. Results: The mean fluoroscopy screening time was 2.18 minutes (0.15 - 6.12) and the mean operation time was 49 minutes (10-150). The mean radiation exposure for patients was 1.307 milisievert (mSv) at kidney location and 0.562 mSv at gonad location per procedure. Surgeon exposure was 0.021 and 0.003 mSv per procedure for hand and leg, respectively. Radiation amounts exposed inside the room and by the surgeon were statistically significantly lower than measured radiation results compared to patient kidney. Conclusion: According to our findings radiation exposure of the patient and the surgeon is below the annual occupational dose limit recommendations. However, for protecting from stochastic effects of radiation, fluoroscopy should be used as low as possible and lead aprons and thyroid shields must be worn to minimize the radiation exposure.Öğe Use of basis sets of ??-exponential type orbitals in calculation of electronic energies for one-electron diatomic molecules by single-zeta approximation(Iop Publishing Ltd, 2008) Guseinov, Israfil Isa; Sahin, E.; Aydin, R.; Bagci, A.The use of complete orthonormal sets of Psi(alpha)-exponential type orbitals (Psi(alpha)-ETOs) is investigated for electronic structure calculations of one-electron diatomic molecular systems. The linear combinations of atomic orbitals (LCAOs) method is used to determine the electronic energy levels of one-electron homonuclear (He-2(3+), Li-2(5+), Be-2(7+) and B-2(9+)) and heteronuclear (HeH2+, LiH3+, BeH4+ and BH5+) molecules by employing the same screening constant for a given set of atomic orbitals of each molecular function. For each molecule, the calculations are carried out for the lowest two energy terms of sigma, pi and delta states using the values of nuclear separations 0.01 <= R <= 20, and Psi(alpha)-ETOs basis sets with alpha = 1, 0 and -1. The results are in good agreement with those found in the literature. The strategies developed in this work can be useful in the study of multielectronic molecules with the help of 9 Psi(alpha)-ETOs basis sets.Öğe Use of combined Hartree-Fock-Roothaan theory in evaluation of lowest states of K[Ar]4s03d1 and Cr+[Ar]4s03d5 isoelectronic series over noninteger n-Slater type orbitals(Indian Acad Sciences, 2011) Guseinov, Israfil Isa; Erturk, M.; Sahin, E.By using noninteger n-Slater type orbitals in combined Hartree-Fock-Roothaan method, self-consistent field calculations of orbital and lowest states energies have been performed for the isoelectronic series of open shell systems K[Ar]4s(0)3d(1) (D-2) (Z = 19-30) and Cr+[Ar]4s(0)3d(5) (S-6) (Z = 24-30). The results of the calculations for the orbital and total energies obtained by using minimal basis-sets of noninteger n-Slater type orbitals are given in the tables. The results are compared with the extended-basis Hartree-Fock computations. The orbital and total energies are in good agreement with those presented in the literature. The results can be useful in the study of various properties of heavy atomic systems when the combined Hartree-Fock-Roothaan approach is employed.
