ePolyScat is a suite of FORTRAN 90 programs and libraries
that can be used to study
electron-molecule scattering processes. Version E has been modified to run on a distributed
memory parallel computer using the MPI message passing library.
The program can be used to study both scattering of electrons from
neutral and ionic molecules and molecular photoionization. The current version of the
codes only treats single electronic states using several different optical potentials
to represent the interaction between the electron and the molecule. The primary potential is
the static-exchange correlation-polarization (SECP) potential. The program can also treat
positron-molecule scattering using a selection of model local potentials.
The codes have been developed as a collaboration of the groups of Lucchese and Gianturco
beginning in 1993. The primary references for the development of the numerical methods used are given below
in the bibliography.
A given calculation uses a series of major subroutines
that exchange information through memory. There is only limited I/O to disk from the
The input file contains data records and commands. The data records are labeled
and the different data records are defined
In order to run correctly, there are a few
which must also be defined.
Finally, there are a number of
which illustrate how the ePolyScat suite can be run.
There are also some
available for major changes in the input and converting source files from the D version to the E version.
Please cite the following two papers when reporting results obtained with this program:
F. A. Gianturco, R. R. Lucchese, and N. Sanna, J. Chem. Phys. 100, 6464 (1994).
A. P. P. Natalense and R. R. Lucchese, J. Chem. Phys. 111, 5344 (1999).
In the root directory of the ePolyScat programs are the following
- contains the executable files
- contains machine specific files for the make command
- contains html files for the online manual
- contains fortran source files
- contains standard tests
The following terms are are used repeatedly in the pages of this manual and are defined
for the purposes of these programs as follows:
- the expansion coefficients of the symmetry adapted
harmonics in the basis set of the
real harmonics. These are described in detail in
S. L. Altmann, "On the symmetries of spherical harmonics,"
Proc. Cambridge Phil. Soc. 53 (Part 2),
- Component of an IR
- the basis function of the irreducible representation,
This is represented by an integer.
- Data record
- a single group of data that are given a symbolic label.
These recodrs are processed using unformatted FORTRAN reads.
- Initial state
- in a photoionization calculation, the initial state is the
unionized bound state.
- irreducible representation, for each point group the various IRs are
represented by either an integer or a five character string.
- Orbital group
- consists of the a set of degenerate molecular orbitals. If
an orbital is nondegenerate then its orbital group just contains
one orbital. For degenerate orbitals, the number of orbitals in the
group is the dimension of the IR which the orbitals transform as.
The members of the group are then indexed the the same manner as the
components of the IR. All of the input in the program are in terms of
orbital groups. For example, one specifies the number of orbital groups
and the occupations of each orbital group.
- Spin degeneracy
- an integer that gives the spin degeneracy of a particular state, i.e.
1 for a singlet, 2 for a doublet, etc.
- Symmetry type
- the full specification of the symmetry of an object including the IR it transforms
as and the component of that IR. This is represented as either a character string
(LEN = 7) or and an integer which indexes the IR and component in a single
list containing all IRs and their components.
- Target state
- the bound state that the electron scatters from.
In a photoionization calculation of a neutral molecule, this is
the ionized state after the photoelectron has left the system.
- Total scattering state
- the combined scattering state including the target
state and the continuum electron.
- F. A. Gianturco, R. R. Lucchese, N. Sanna, and A. Talamo, A Generalized
Single Center Approach for Treating Electron Scattering from Polyatomic
Molecules, in Electron Collisions with Molecules, Clusters, and Surfaces,
edited by H. Ehrhardt and L. A. Morgan, (Plenum, New York, 1994) pp. 71-86.
- F. A. Gianturco, R. R. Lucchese, and N. Sanna, On the Scattering of Low-Energy
Electrons by Sulphur Hexafluoride, J. Chem. Phys. 102, 5743-5751 (1995).
- Robert R. Lucchese and F. A. Gianturco, One-Electron Resonances in
Electron Scattering from Polyatomic Molecules, Intern. Rev. Phys. Chem. 15, 429-466 (1996).
- F. A. Gianturco and Robert R. Lucchese, One-Electron
Resonances and Computed Cross Sections in Electron Scattering
from the Benzene Molecule, J. Chem. Phys. 108, 6144-6159 (1998).
- F. A. Gianturco, R. R. Lucchese, and N. Sanna, Computed
elastic cross sections and angular distributions of
low-energy electron scattering from gas phase C60 fullerene,
J. Phys. B 32, 2181-2193 (1999).
- Alexandra P. P. Natalense and Robert R. Lucchese,
Cross section and asymmetry parameter calculation for
sulfur 1s photoionization of SF6,
J. Chem. Phys. 111, 5344-5348 (1999); Erratum, J. Chem. Phys. 112, 501 (2000).
- F. A. Gianturco and Robert R. Lucchese, One-particle resonances in low-energy
electron scattering from C60, J. Chem. Phys. 111, 6769-6786 (1999).
- F. A. Gianturco and Robert R. Lucchese, A computational
investigation of positron scattering from C60, Phys. Rev. A 60, 4567-4576 (1999).
- F. A. Gianturco and R. R. Lucchese, Electron scattering from
gaseous SF6: Comparing calculations with experiments, J. Chem. Phys. 114, 3429-3439 (2001).