Question about parameter in qfile for fix qeq/point command

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1

Hi LAMMPS users,

I have a minor question about the eta parameter used in the qfile for the fix qeq/point command.
In the LAMMPS documentation eta is defined as the self-Coulomb potential.

After consulting one of the cited articles (Rappe and Goddard, J. Phys. Chem. 1991, 95 3358-3363) they say eta (given by Parr and Pearson) is the atomic hardness defined as half of the self-Coulomb potential (which they define as J in this paper.)

My question is do I input the value for the self-Coulomb potential or atomic hardness into the qfile.
I apologize if this is obvious, I just wanted to be sure as the notation is throwing me off slightly.

Thank you,
Joseph Vella
PhD Candidate
Department of Chemical & Biological Engineering
Princeton University

2

Hi LAMMPS users,

I have a minor question about the eta parameter used in the qfile for
the fix qeq/point command.
In the LAMMPS documentation eta is defined as the self-Coulomb potential.

After consulting one of the cited articles (Rappe and Goddard, J. Phys.
Chem. 1991, 95 3358-3363) they say eta (given by Parr and Pearson) is the
atomic hardness defined as half of the self-Coulomb potential (which they
define as J in this paper.)

My question is do I input the value for the self-Coulomb potential or
atomic hardness into the qfile.
I apologize if this is obvious, I just wanted to be sure as the notation
is throwing me off slightly.

To be consistent with the existing fix qeq/reax command, eta parameter in
fix qeq/* is the atomic hardness (or the self-Coulomb potential) NOT
divided by 2. So you will have to multiply eta from the Rappe Goddard
paper by 2.

Cheers,
Ray