A polynomial approximation for the scattering wavefunction of an arbitrary spherically symmetric potential

A new variational approach is proposed to calculate scattering phase shifts. In this approach, the variational parameter is contained not explicitly in the trial function but in the boundary conditions that the scattering wavefunction should satisfy. It was found that a high accuracy could be reached. Furthermore, the scattering wavefunction appears as a polynomial of finite orders in the interior region. This expression is convenient for applications.