Yazar "Mamedov, BA" seçeneğine göre listele
Listeleniyor 1 - 20 / 35
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A new algorithm for accurate and fast evaluation of the Hubbell radiation rectangular source integral(Pergamon-Elsevier Science Ltd, 2005) Guseinov, Israfil Isa; Mamedov, BA; Ekenoglu, ASIn this work we present a new efficient and reliable analytical procedure for evaluation of the Hubbell radiation rectangular source (HRS) integral using a binomial expansion. The proposed procedure guarantees the reliable evaluation of the radiation field generated by a plane isotropic rectangular source (plaque) of scaled width and length a and b, respectively. The formulas obtained are numerically stable for a(2) + b(2) < 1. Numerical results are presented and compared with results using alternative evaluation schemes. (C) 2005 Elsevier Ltd. All rights reserved.Öğe Algorithm for the storage of Clebsch-Gordan and Gaunt coefficients with the same selection rule and its application to multicenter integrals(Elsevier Science Bv, 2005) Guseinov, Israfil Isa; Mamedov, BACommon algorithm is presented for the generation and storage of all unique, non-zero Clebsch-Gordan and Gaunt coefficients for which the sum of the three angular momentum quantum numbers is a non-negative even integer. This algorithm is especially useful for the fast computation of arbitrary multicenter integrals over Slater type orbitals (STOs) appearing in the Hartree-Fock-Roothaan and Hylleraas approaches. The storage algorithm obtained for the Clebsch-Gordan and Gaunt coefficients is utilized, as for examples, in the computation of two-electron multicenter integrals occurring in the Hartree-Fock-Roothaan equations of a molecule. (c) 2004 Elsevier B.V. All rights reserved.Öğe Algorithm for the storage of expansion coefficients for the product of associated Legendre functions in elliptical coordinates useful for the calculations of molecular integrals(Elsevier, 2004) Guseinov, Israfil Isa; Mamedov, BAAn algorithm is presented for the generation and storage of expansion coefficients for the product of two associated Legendre functions both with different centers introduced by the one of authors [J. Phys. B 3 (1970) 1399] for the calculation of multicenter integrals over STOs using auxiliary functions. The formulae for retrieving these coefficients in a non-sequential fashion are developed and presented. We believe that the use of formulae given in this work for the storage of expansion coefficients will have important contributions in reducing requirements for computer time in the calculation of molecular integrals with the aid of auxiliary functions. (C) 2004 Elsevier B.V. All rights reserved.Öğe Calculation of arbitrary overlap integrals over type orbitals using basic overlap integrals(Huazhong Univ Sci Tech Press, 2000) Guseinov, Israfil Isa; Mamedov, BA; Orbay, M; Özdogan, TThe recurrence relations are presented for the calculation of basic overlap integrals, by making use of which other overlap integrals are calculated analytically. These recurrence relations are especially useful for the calculation of any overlap integral for large quantum numbers. For the arbitrary values of screening constants of atomic orbitals and internuclear distances an accuracy of the computer results is satisfactory for the values of principal quantum numbers of Slater functions up to 50.Öğe Calculation of electric multipole moment integrals using translation formulas for Slater-type orbitals(Huazhong Univ Sci Tech Press, 2000) Guseinov, Israfil Isa; Mamedov, BA; Orbay, M; Özdogan, T; Rzaeva, AM; Gasanov, AGUsing translation formulas for Slater-type orbitals the infinite series through the overlap integrals are derived for the electric multipole moment integrals. By the use of the derived expressions the electric multipole moment integrals, and therefore, the electric properties of molecules can be evaluated most efficiently and accurately. The convergence of the series is tested by calculating concrete cases. An accuracy of 10(-5) for the computer results is obtained for 1 less than or equal to v less than or equal to 5, and for the arbitrary values of internuclear distances and screening constants of atomic orbitals.Öğe Calculation of generalized secant integral using binomial coefficients(Pergamon-Elsevier Science Ltd, 2004) Guseinov, Israfil Isa; Mamedov, BAA single series expansion relation is derived for the generalized secant (GS) integral in terms of binomial coefficients, exponential integrals and incomplete gamma functions. The convergence of the series is tested by the concrete cases of parameters. The formulas given in this study for the evaluation of GS integral show good rate of convergence and numerical stability. (C) 2003 Elsevier Ltd. All rights reserved.Öğe Calculation of magnetic multipole moment integrals using translation formulas for Slater-type orbitals(Indian Academy Sciences, 1999) Guseinov, Israfil Isa; Mamedov, BA; Özdogan, T; Orbay, MUsing translation formulas for Slater type orbitals (STO's) the infinite series through the overlap integrals are derived for the magnetic multipole moment integrals. By the use of the derived expressions the magnetic multipole moment integrals, therefore, the magnetic properties of molecules can be evaluated most efficiently and accurately. The convergence of the series is tested by calculating concrete cases. An accuracy of 10(-5) for the computer results is obtained in the case 2(nu)-pole magnetic moment integrals for 1 less than or equal to nu less than or equal to 5, and for the arbitrary values of internuclear distances and screening constants of atomic orbitals.Öğe Calculation of molecular electric and magnetic multipole moment integrals of integer and noninteger n Slater orbitals using overlap integrals(John Wiley & Sons Inc, 2003) Guseinov, Israfil Isa; Mamedov, BAClosed formulas are established for the magnetic multipole moment integrals of integer and noninteger n Slater-type orbitals (ISTOs and NISTOs) in terms of electric multipole moment integrals for which the analytic expressions through the overlap integrals with ISTOs and NISTOs are derived. The overlap integrals are evaluated by the use of auxiliary functions. Using the derived expressions the multipole moment integrals, and therefore the electric and magnetic properties of molecules, can be evaluated most efficiently and accurately. (C) 2003 Wiley Periodicals, Inc.Öğe Calculation of multicenter electronic attraction, electric field and electric field gradient integrals of Coulomb potential over integer and noninteger n Slater orbitals(Springer, 2005) Guseinov, Israfil Isa; Mamedov, BAWith the help of complete orthonormal sets of psi(alpha) - ETOs, where alpha = 1, 0,- 1,- 2,... a large number of series expansion formulas for the multicenter electronic attraction ( EA), electric field ( EF) and electric field gradient ( EFG) integrals of integer and noninteger n Slater type orbitals ( ISTOs and NISTOs) is established through the overlap integrals with the same screening constants and the new central and noncentral interaction potentials depending on the coordinates of the nuclei of a molecule are introduced. The convergence of the series is tested by calculating concrete cases for arbitrary quantum numbers, screening constants and location of ISTOs and NISTOs.Öğe Calculation of multicenter nuclear attraction and electron repulsion integrals over Slater orbitals by Fourier transform method using Gegenbauer polynomials(Kluwer Academic/Plenum Publ, 2002) Guseinov, Israfil Isa; Mamedov, BAIn this study, using complete orthonormal sets of exponential type orbitals (ETOs), a single closed analytical relation is derived for a large number of different expansions of overlap integrals over Slater type orbitals (STOs) with the same screening parameters in terms of Gegenbauer coefficients. The general formula obtained for the overlap integrals is utilized for the evaluation of multicenter nuclear attraction and electron repulsion integrals appearing in the Hartree-Fock-Roothaan equations for molecules. The formulas given in this study for the evaluation of these multicenter integrals show good rate of convergence and great numerical stability under wide range of quantum numbers, scaling parameters of STOs and internuclear distances.Öğe Calculation of overlap integrals over Slater-type orbitals using translational and rotational transformations for spherical harmonics(Springer-Verlag, 2000) Guseinov, Israfil Isa; Mamedov, BAUsing translation and rotation formulas for spherical harmonics the finite sums through the basic overlap integrals and spherical harmonics are derived for the arbitrary overlap integrals over Slater-type orbitals (STOs). The recurrence relations for the evaluation of basic overlap integrals have been established recently [Guseinov II, Mamedov BA (1999) J Mol Struct (THEOCHEM 465:1]. By the use of the derived expressions the overlap integrals can be calculated most efficiently and accurately, especially for large quantum numbers of STOs.Öğe Calculation of the generalized Hubbell rectangular source integrals using binomial coefficients(Elsevier Science Inc, 2005) Guseinov, Israfil Isa; Mamedov, BAThe series expansion formulas in terms of binomial coefficients are derived for the family of generalized source integrals (HRSIs) appearing in the evaluation of radiation field from a plane isotropic rectangular source. The formulas given in this study for the evaluation of radiation integrals-HRSIs show good rate of convergence and great numerical stability. The results obtained by the present approach are found to be in excellent agreement with other theoretical studies. (C) 2004 Elsevier Inc. All rights reserved.Öğe Calculation of three-center electric and magnetic multipole moment integrals using translation formulas for Slater-type orbitals(Springer-Verlag, 2000) Guseinov, Israfil Isa; Mamedov, BA; Orbay, MBy the use of translation formulas for the expansion of Slater-type orbitals (STOs) in terms of STOs at a new origin, three-center electric and magnetic multipole moment integrals are expressed in terms of two-center multipole moment integrals for the evaluation of which closed analytical formulas are used. The convergence of the series is tested by calculating concrete cases. Computer. results with an accuracy of 10(-7) are obtained for 2(v) pole electric and magnetic multipole moment integrals for 1 less than or equal to v less than or equal to 5 and for arbitrary values of screening constants of atomic orbitals and internuclear distances.Öğe Computation of molecular integrals over Slater-type orbitals. III. Calculation of multicenter nuclear-attraction integrals using recurrence relations for overlap integrals(Elsevier Science Bv, 2000) Guseinov, Israfil Isa; Aydin, R; Mamedov, BAUsing recurrence relations for basic overlap integrals two- and three-center nuclear-attraction integrals are calculated for extremely large quantum numbers. The accuracy of the results is quite high for the principal quantum numbers of Slater functions and for the arbitrary values of internuclear distances and screening constants of atomic orbitals. (C) 2000 Elsevier Science B.V, All rights reserved.Öğe Computation of molecular integrals over Slater-type orbitals. IV. Calculation of multicenter electron-repulsion integrals using recurrence relations for overlap integrals(Elsevier Science Bv, 2000) Guseinov, Israfil Isa; Mamedov, BA; Aydin, RUsing formulas given by one of the authors [I.I. Guseinov, J. Mel. Struct. (Theochem) 417 (1997) 117], the multicenter electron-repulsion integrals with the arbitrary location and screening constants of Slater-type orbitals (STOs) are calculated for extremely large quantum numbers. Accuracy of the results is quite high for quantum numbers n, l and m of STOs. (C) 2000 Elsevier Science B.V. All rights reserved.Öğe Computation of molecular integrals over Slater-type orbitals. V. Calculation of multicenter electron-repulsion integrals using auxiliary functions(Elsevier Science Bv, 2000) Guseinov, Israfil Isa; Mamedov, BAThe multicenter electron-repulsion integrals appearing in the Hartree-Fock-Roothaan (HFR) equations for molecules are expressed in terms of the overlap integrals and the basic two-center Coulomb or hybrid integrals by the use of expansion formulas for the charge-density over Slater-type orbitals (STOs) obtained by the one of authors (I.I. Guseinov, J. Mel. Struct. (Theochem) 417 (1997) 117), For the calculation of basic integrals the new auxiliary functions are introduced. The multicenter electron-repulsion integrals are calculated for extremely large quantum numbers using recurrence relations for the overlap integrals and auxiliary functions, (C) 2000 Elsevier Science B.V. All rights reserved.Öğe Computation of molecular integrals over Slater-type orbitals. VII. Calculation of multielectron molecular integrals by single-center expansion method using different translation formulas(Elsevier Science Bv, 2001) Guseinov, Israfil Isa; Mamedov, BA; Rzaeva, AMHitherto known formulas for the translation of Slater-type orbitals (STOs) from one center to another encounter serious difficulties in practical applications. In contrast, those derived by the use of arbitrary complete orthonormal sets of exponential-type functions (ETFs) expansion formulas appear to be free of these difficulties. We have examined in this paper the applicability of translation formulas for STOs obtained from the two kinds of ETFs, namely, from the Lambda (A) and Coulomb Sturmian (CS) functions (Int. J. Quant. Chem. 81 (2001) 126) to the quantum-mechanical multicenter problems from the computational point of view and found it very useful. Test calculations on three-center nuclear attraction and four-center electron-repulsion integrals by single-center expansion method are reported. It is shown that these integrals in the case of Coulomb Sturmian ETFs exhibit a faster convergence rate. Therefore, it is recommended to use the expansion formulas for translation of STOs, obtained from the Coulomb Sturmian ETFs, in the calculation of multielectron multicenter molecular integrals. (C) 2001 Elsevier Science B.V. All rights reserved.Öğe Computation of molecular integrals over Slater-type orbitals.: VIII.: Calculation of overlap integrals with different screening parameters using series expansion formulas for Slater-type orbitals(Elsevier Science Bv, 2001) Guseinov, Israfil Isa; Mamedov, BA; Öner, F; Hüseyin, SUsing expansion formulas for the Slater-type orbitals (STOs) obtained by the one of authors [Phys. Rev. A 31 (1985) 2851] the two-center overlap integrals with different screening parameters are expressed through the overlap integrals with the same screening parameter. The series representation of overlap integrals obtained in this paper is useful for small differences of the exponential parameters. For large differences of the exponential parameters the convergence of the infinite series becomes rather slow. (C) 2001 Elsevier Science B.V. All rights reserved.Öğe Computation of molecular integrals over Slater-type orbitals.: X.: Calculation of overlap integrals with integer and noninteger n Slater orbitals using complete orthonormal sets of exponential functions(Elsevier Science Bv, 2002) Guseinov, Israfil Isa; Mamedov, BA; Sünel, NUsing two kinds of complete orthonormal sets of exponential-type orbitals, the series expansion formulas are derived for the overlap integrals with noninteger n(*) Slater-type orbitals (NISTOs) in terms of overlap integrals over integer n Slater-type orbitals with the same and different screening constants. The convergence of the series is tested by calculating concrete cases for arbitrary values of noninteger principal quantum numbers and screening constants of NISTOs and internuclear distances. (C) 2002 Elsevier Science B.V. All rights reserved.Öğe Convergence of translation formulas for the computation of multicenter integrals over Slater orbitals(Academic Press Inc Elsevier Science, 2001) Guseinov, Israfil Isa; Mamedov, BAMulticenter electron-repulsion integrals are calculated using auxiliary functions and two kinds of translation formulas for Slater-type orbitals (STOs) obtained from the expansion of STOs, in terms of exponential-type orbitals at a displaced center, that form complete orthonormal sets and are represented by linear combinations of STOs. The convergence of the series for real STOs is tested by calculating concrete cases. Accuracy of the results is quite high for quantum numbers, screening constants, and location of STOs. (C) 2001 Elsevier Science.
