A function to test methods applied to global minimization of potential energy of molecules

In this paper we develop a function with a functional form similar to general potential energy functions and whose global minimum is known. We prove that the number of local minimizers of this function increases exponentially with the size of the problem, which characterizes the principal difficulty in minimizing molecular potential energy functions. In order to guarantee the global optimality and to show the difficulty in obtaining the global minimum of this function, we propose the utilization of a deterministic algorithm. The algorithm is based on a branch and bound scheme that uses interval analysis techniques to calculate the lower bounds. Computational results for problems with up to 25 degrees of freedom are presented.