Electron-molecule scattering and molecular photoionization using the multiple-scattering method

We adapt the multiple-scattering method to treat unbound electronic states of molecules in the independent electron approximation. An inhomogeneous linear system is derived whose solution yields the K matrix for the electron-molecule interaction. Using the K matrix, we derive continuum electronic wavefunctions by imposing boundary conditions corresponding to electron-molecule scattering and molecular photoionization, i.e., the wavefunctions satisfy the so-called outgoing-wave and incoming-wave normalization, respectively. These wavefunctions are then used to obtain expressions for elastic scattering and photoionization differential cross sections.