The Real Exact Solutions to the Hyperbolic Scarf Potential
  The exact solutions of the Schrodinger equation with the hyperbolic Scarf potential reported in the literature so far rely upon Jacobi polynomials with imaginary arguments and parameters. We here show that upon a suitable factorization these solutions can be expressed alternatively by means of real orthogonal polynomials distinct but the classical ones as they satisfy a new self-adjoint differential equation of the hypergeometric type. 
D. E. Alvarez-Castillo, M.Kirchbach