Finding appropriate zeta and qcore parameters for fix qeq/slater?


I am currently working with 30 July 2016 version of LAMMPS. I am hoping to use fix qeq/slater, which implements the Streitz-Mintsmire method. It is relatively easy to find the chi and eta parameters I need, and consequently I have been able to run fix qeq/point. However, I am having difficulty finding the appropriate parameters to use for zeta and qcore for my atoms of interest.

Do you have suggestion on where to find these parameters? Or if you have a list of standard atomic parameters that users can use, that’d be very helpful as well.

Thank you very much, and best regards


Zeta describes the exponential decay of the electron density around a nucleus, and qcore describes the effective core charge of the nucleus. Together with chi and eta, these four parameters are usually fitted to experimental data such as ionization energy and electron affinity, as well as to results from electronic structure calculations such as Bader charge and calculated ionization energies/electron affinities (when experimental values are not available).

When you have to run some electronic structure calculations to fit the zeta and qcore parameters, practically speaking the chi and eta parameters are also fitted. In practice, VASP works well for Bader charges and Gaussian works well for ionization energies.