Computation of the Eigenvalues of the Schrödinger Equation by Exponentially‐Fitted Runge‐Kutta‐Nyström Methods

In this work we consider exponentially fitted Runge Kutta Nyström methods. These methods integrate exactly differential systems whose solutions can be expressed as linear combinations of the set of functions $exp(wx),$ $exp(−wx),$ or $sin(wx),cos(wx),$ $w∈R.$ We modify existing RKN methods order four to six and apply these methods to the computation of the eigenvalues of the Schrödinger Equation.