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Manuscript Title: Evaluation of a general three-denominator Lewis integral. | ||

Authors: U. Roy, L.J. Dube, P. Mandal, N.C. Sil | ||

Program title: LEWIS | ||

Catalogue identifier: ADCO_v1_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 92(1995)277 | ||

Programming language: Fortran. | ||

Computer: PC Pentium-100. | ||

Operating system: MS DOS v. 6.2, SOLARIS v. 2.x. | ||

Word size: 64 | ||

Keywords: Three-denominator lewis Integrals, Dalitz integration, Variational and Collisional calculations, General purpose, Quadrature, Analytic, Contour integration. | ||

Classification: 4.11. | ||

Nature of problem:Structural and collisional studies in atomic, molecular and nuclear physics often encounter a certain type of 3-denominator integrals in the course of the calculations [1]. These integrals (called here general Lewis integrals [2]) appear naturally whenever two or more centres of force are present and relative coordinates of the interacting particles are involved. We derive a closed analytic form for these integrals and demonstrate by a few examples the usefulness of the results. | ||

Solution method:Expressions for a general class of 3-denominator Lewis integrals are obtained by contour integration as a sum of two finite series, thereby avoiding parametric differentiation of a complicated closed form. Analytical methods are employed throughout, thus enabling high accuracy and efficiency of the calculations. | ||

Restrictions:The highest order of the derivatives of the Lewis integrals is limited to 3 and the parameters (mu0,mu1,mu2) and variables (q1,q2) are taken to be real. | ||

References: | ||

[1] | C.J. Joachain, Quantum collision theory (North-Holland, Amsterdam, 1983) | |

[2] | R.R. Lewis, Phys Rev A102 (1956) 537 |

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