Exponentially fitted Runge-Kutta fourth algebraic order methods for the numerical solution of the Schrodinger equation and related problems

Fourth order exponential and trigonometric fitted Rung-Kutta methods are de veloped in this paper. They are applied to problems involving the Schroding er equation and to other related problems. Numerical results show the super iority of these methods over conventional fourth order Runge-Kutta methods. Based on the methods developed in this paper, a variable-step algorithm is proposed. Numerical experiments show the efficiency of the new algorithm.