Data sets for the publication "Repulsive interatomic potentials calculated at three levels of theory" by K. Nordlund, S. Lehtola and G. Hobler.

This file system package contains data sets for the publication "Repulsive interatomic potentials calculated at three levels of theory" by K. Nordlund, S. Lehtola and G. Hobler. It presents three quantum chemically calculated data sets ("MP2", "DMol", and "ZBL pair-specific") for diatomic interatomic potentials in the repulsive region, where the separation of the atoms is so short that the potential energy is >> 10 eV. The set also contains the fitted parameters for analytical NLH repulsive potentials that consist of a Coulomb term multiplied by a three-exponential screening function.

The version from Oct 9, 2025 has updated NLH parameters for the pair Na-O (Z1=8, Z2=11). Otherwise the data is identical to before.

The version from Aug 25, 2026 has an additional directory with the NLHlin analytical potentials to be published in a separate paper. These potentials are similar to the NLH potentials, but are cut off to exactly 0 at the distance where the DMol data turns to negative. 

The MP2 data sets contain potential data for all elements pairs Z1+Z2<=36, and the DMol, ZBL pair-specific and NLH potentials are proved for all elements pairs Z1, Z2 <=92.

The data sets are arranged in the following directories:

mp2/      : Data sets for the Hartree-Fock Moller-Plesset2 level calculations

dmol/     : Data sets for the Density Functional Theory calculations with the DMOL code

nlh/      : Coefficients for the fits of the Nordlund-Lehtola-Hobler potential to the DMol data sets [1]

nlhlin/   : Coefficients for the fits of the finite-range Nordlund-Lehtola-Hobler potential [2] to the DMol data sets and coefficients for nuclear stopping cross sections and stragglings.

zbl/      : Data sets for the pair-specific Ziegler-Biersack-Littmark potential calculations

zbluniv/  : A directory with a Linux bash/awk script that generates the ZBL universal potential.

zblspec/  : Coefficients for the pair-specific ZBL screening functions as contained in SRIM-2013.

Each subdirectory has its own README.txt file giving additional details on the content of the directory and its subdirectories.

[1] "Repulsive interatomic potentials calculated at three levels of theory"
by K. Nordlund, S. Lehtola and G. Hobler, published as Physical Review A 111, 032818 (2025).
and
[2] "Finite-range repulsive interatomic potentials for binary collision approximation simulations"
by G. Hobler and K. Nordlund, submitted to Nuclear Instruments and Methods in Physics Research B.