Title: I need some clarifications on the Coulomb interaction in Lammps.
For pair potentials such as Born?CMayer?CHuggins, there is an adding Coulombic pairwise interaction which is expressed as: (Page 1103 in the latest Manual).
C is an energyconversion constant. However, in some references(Masahiko Matsumiya, Ryuzo Takagi, Electrochimica Acta 46 (2001) 3563?C3572), the Coulombic interaction is:
Otherwise, some other references (Jamshed Anwar et al, J. Chem. Phys., Vol. 118, No. 2, 8 January 2003) formulate the Coulombic interaction as: .
My questions:

What is the energyconversion constant means? What is the value and unit of it? Does it have any relationships with the electrostatic constant?

Why the energyconversion constant is ignored sometimes? Should I modify the energyconversion constant to satisfy the references’ expressions? If so, how to modify the energyconversion constant.

Does the charge numbers are always integers? E.g. the charge of Na+ in NaCl is +1 with enough precision?
Thank you very much!
Title: I need some clarifications on the Coulomb interaction in Lammps.
For pair potentials such as Born–Mayer–Huggins, there is an adding
Coulombic pairwise interaction which is expressed as: (Page 1103 in the
latest Manual).
C is an energyconversion constant. However, in some references(Masahiko
Matsumiya, Ryuzo Takagi, Electrochimica Acta 46 (2001) 3563–3572), the
Coulombic interaction is:
Otherwise, some other references (Jamshed Anwar et al, J. Chem. Phys.,
Vol. 118, No. 2, 8 January 2003) formulate the Coulombic interaction as: .
My questions:
1. What is the energyconversion constant means? What is the value
and unit of it? Does it have any relationships with the electrostatic
constant?
it is essentially a unit conversion factor. its value depends on what unit
of energy and what units of charge you have.
2. Why the energyconversion constant is ignored sometimes? Should I
modify the energyconversion constant to satisfy the references’
expressions? If so, how to modify the energyconversion constant.
see answer to question 1.
3. Does the charge numbers are always integers? E.g. the charge of
Na+ in NaCl is +1 with enough precision?
no. that is model dependent, but for salts it is often chosen to be
integers.
axel.