Relaxation Energies in Photoemission


Our REPS program can be used to calculate core-level relaxation energies in photoelectron spectroscopy by the equivalent-core approximation.

Two output files from the GAUSSIAN program (not included) are needed to start a REPS calculation.

Firstly, the ground-state of an atom or molecule is determined by minimizing the total energy with ab initio Hartree-Fock self consistent calculations with a standard basis set. The one-electron eigenvalues and molecular coefficients for each orbital, as well as all the two-electron Coulomb and exchange integrals for the individual primitive Gaussian functions are obtained based on an optimized geometry using the same basis set.

Secondly, the above calculations are to be repeated for the equivalent ion-core ion state, with the same atomic or molecular geometry and basis set.


Documentation is provided in the file reps.txt, which is included in the downloaded container file.

Computer platforms

The REPS program is written in C++, and supplied as source code. It can run on any computer for which a C++ compiler is available. The container file should be unzipped with WinZip (or equivalent) on a PC/Windows system.

Conditions of use

The programs can be downloaded for free and may be freely used, but not distritibuted. We ask that new users obtain copies from this web site. No guarantee of correct results can be given: the calculations are performed at the users' own risk.


The authors require that an acknowledgment be included in publications, such as: "The calculations were performed using the Berkeley REPS program." Also, a reference to the origin of the program should be included in your publications, as follows:

Downloading REPS


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