The ePolyScat codes compute electron-molecule scattering and molecular photoionization cross sections [1,2] within the fixed-nuclei approximation. Using the adiabatic approximation, it is possible to extract ro-vibrationally resolved cross sections. The code uses simple, single configuration initial and target states wave functions, and the final continuum state is limited to a single electronic state. The interaction potential between the electron and the molecule is then given by the static-exchange potential, which can be modified by approximate functionals to describe target polarization effects. The calculations are performed in the full symmetry point group for the molecular geometry, including both abelian and many non-abelian point groups. An external source of bound molecular orbitals is required for ePolyScat, and these orbitals may be obtained from GAUSSIAN, GAMESS(US), MESA, and from MOLPRO using a molden file. The continuum wave functions are obtained as single-center expansions using products of symmetry-adapted angular harmonics and radial functions represented on a grid of points. The size of the single-center expansion is controlled by a maximum angular momentum parameter, and the density of the radial grid is controlled by a maximum energy parameter.

  • Developers: R. R. Lucchese, A. P. P. Natalense, J. Lopez Dominguez, N. Sanna, and F. A. Gianturco.
  • The code is written in Fortran2003 and uses MPI and LAPACK libraries. The current version can efficiently use up to about 32 processes but requires at least two.
  • The source code is available by request from Robert Lucchese.
  • On-line documentation. Contains many examples of electron scattering and molecular photoionization calculations and includes defining environment variables, and the use of the Makefile to compile the program.
  • ePolyScat website

[1] A. P. P. Natalense and R. R. Lucchese, Cross section and asymmetry parameter calculation for sulfur 1s photoionization of SF6, J. Chem. Phys. 111 (12), 5344 (1999).

[2] F. A. Gianturco, R. R. Lucchese, and N. Sanna, Calculation of low-energy elastic cross sections for electron-CF4 scattering, J. Chem. Phys. 100 (9), 6464 (1994).