diff --git a/doc/src/pair_charmm.txt b/doc/src/pair_charmm.txt index 9c5973c7255e240b5da207e9458c770198cfed43..1e78607c084e6b4ac07bca1cc8ec39a5a6585d80 100644 --- a/doc/src/pair_charmm.txt +++ b/doc/src/pair_charmm.txt @@ -104,7 +104,15 @@ charmmfsw"_dihedral_charmm.html command. Eventually code from the new styles will propagate into the related pair styles (e.g. implicit, accelerator, free energy variants). -The general CHARMM formulas are as follows +NOTE: The newest CHARMM pair styles reset the Coulombic energy +conversion factor used internally in the code, from the LAMMPS value +to the CHARMM value, as if it were effectively a parameter of the +force field. This is because the CHARMM code uses a slightly +different value for the this conversion factor in "real +units"_units.html (Kcal/mole), namely CHARMM = 332.0716, LAMMPS = +332.06371. This is to enable more precise agreement by LAMMPS with +the CHARMM force field energies and forces, when using one of these +two CHARMM pair styles. :c,image(Eqs/pair_charmm.jpg) diff --git a/doc/src/pair_dipole.txt b/doc/src/pair_dipole.txt index a9622b32fd877ab79c5d51b02d0ab46133c5bee3..985581cac8b227ad8ee3a75ec187ef13c985068b 100644 --- a/doc/src/pair_dipole.txt +++ b/doc/src/pair_dipole.txt @@ -71,6 +71,14 @@ and force, Fij = -Fji as symmetric forces, and Tij != -Tji since the torques do not act symmetrically. These formulas are discussed in "(Allen)"_#Allen2 and in "(Toukmaji)"_#Toukmaji2. +Also note, that in the code, all of these terms (except Elj) have a +C/epsilon prefactor, the same as the Coulombic term in the LJ + +Coulombic pair styles discussed "here"_pair_lj.html. C is an +energy-conversion constant and epsilon is the dielectric constant +which can be set by the "dielectric"_dielectric.html command. The +same is true of the equations that follow for other dipole pair +styles. + Style {lj/sf/dipole/sf} computes "shifted-force" interactions between pairs of particles that each have a charge and/or a point dipole moment. In general, a shifted-force potential is a (sligthly) modified