Spectral singularities of Klein-Gordon s-wave equations with an integral boundary condition

We investigate the spectral singularities and the eigenvalues of the boundary value problem $$begin{gathered} y'' + left[ {lambda - Qleft( x right)} right]^2 y = 0,x in R_ + = [0,infty ), hfill quad intlimits_0^infty {Kleft( x right)yleft( x right)dx + alpha y'left( 0 right) - beta yleft( 0 right) = 0,} hfill end{gathered}$$ where Q and K are complex valued functions, K∈L ²(R ₊), α,β∈C with |α|+|β|≠0 and λ is a spectral parameter.