UDC 517.958:530.145.6 Description of a Program for Computing Eigenvalues and Eigenfunctions and Their First Derivatives with Respect to the Parameter of the Coupled Parametric Self-Adjoined Elliptic Differential Equations A. A. Gusev∗, O. Chuluunbaatar†, S. I. Vinitsky∗, A. G. Abrashkevich‡ ∗ Joint Institute for Nuclear Research 6, Joliot-Curie, Dubna, Moscow region, Russia, 141980 † School of Mathematics and Computer Science National University of Mongolia, Mongolia ‡ IBM Toronto Lab, 8200 Warden Avenue, Markham, ON L6G 1C7, Canada Brief description of a FORTRAN 77 program is presented for calculating with the given accuracy eigenvalues, eigenfunctions and their first derivatives with respect to the parameter of the coupled parametric self-adjoined elliptic differential equations with the Dirichlet and/or Neumann type boundary conditions on the finite interval. <...> The original problem is projected to the parametric homogeneous and nonhomogeneous 1D boundary-value problems for a set of ordinary second order differential equations which is solved by the finite element method. <...> The program calculates also potential matrix elements – integrals of the eigenfunctions multiplied by their first derivatives with respect to the parameter. <...> Parametric eigenvalues (so-called potential curves) and matrix elements computed by the POTHEA program can be used for solving the bound state and multi-channel scattering problems for a system of the coupled second-order ordinary differential equations with the help of the KANTBP programs. <...> As a test desk, the program is applied to the calculation of the potential curves and matrix elements of Schr¨ odinger equation for a system of three charged particles with zero total angular momentum. <...> Key words and phrases: boundary value problem, finite element method, Kantorovich method. 1. <...> Introduction ing with a given accuracy eigenvalues, eigenfunctions and their first derivatives with respect to the parameter of the coupled parametric self-adjoined elliptic differential equations with the Dirichlet and/or Neumann type boundary conditions on the finite interval [1]. <...> The original problem is projected to the parametric homogeneous and nonhomogeneous 1D BVPs for a set of ordinary second order differential equations which is solved by the finite element method [2]. <...> Potential curves and matrix elements computed by the POTHEA program can be In this work we present a brief description of a POTHEA program for calculatused for solving the bound <...>