list possible pair styles with SPC Howto. Add comment about cutof vs. long-range coulomb

doc/src/Howto_spc.rst

@@ -8,6 +8,18 @@ the two O-H bonds and the H-O-H angle rigid.  A bond style of
 *harmonic* and an angle style of *harmonic* or *charmm* should also be
 used.
 
+One suitable pair style with cutoff Coulomb would for instance be:
+
+* :doc:`pair_style lj/cut/coul/cut <pair_lj_cut_coul>`
+
+These commands are examples for a long-range Coulomb model:
+
+* :doc:`pair_style lj/cut/coul/long <pair_lj_cut_coul>`
+* :doc:`pair_style lj/cut/coul/long/soft <pair_fep_soft>`
+* :doc:`kspace_style pppm <kspace_style>`
+* :doc:`pair_style lj/long/coul/long <pair_lj_long>`
+* :doc:`kspace_style pppm/disp <kspace_style>`
+
 These are the additional parameters (in real units) to set for O and H
 atoms and the water molecule to run a rigid SPC model.
 
@@ -39,7 +51,9 @@ the SPC and SPC/E models.
 Below is the code for a LAMMPS input file and a molecule file
 (``spce.mol``) of SPC/E water for use with the :doc:`molecule command
 <molecule>` demonstrating how to set up a small bulk water system for
-SPC/E with rigid bonds.
+SPC/E with rigid bonds.  For simplicity and speed the example uses a
+cutoff Coulomb.  Most production simulations require long-range Coulomb
+instead.
 
 .. code-block:: LAMMPS
 

doc/src/Howto_tip3p.rst

@@ -5,17 +5,24 @@ The TIP3P water model as implemented in CHARMM :ref:`(MacKerell)
 <howto-tip3p>` specifies a 3-site rigid water molecule with charges and
 Lennard-Jones parameters assigned to each of the three atoms.
 
-A suitable pair style with cutoff Coulomb would be:
+One suitable pair style with cutoff Coulomb would for instance be:
 
 * :doc:`pair_style lj/cut/coul/cut <pair_lj_cut_coul>`
 
-or these commands for a long-range Coulomb model:
+These commands are examples for a long-range Coulomb model:
 
 * :doc:`pair_style lj/cut/coul/long <pair_lj_cut_coul>`
 * :doc:`pair_style lj/cut/coul/long/soft <pair_fep_soft>`
 * :doc:`kspace_style pppm <kspace_style>`
+* :doc:`pair_style lj/long/coul/long <pair_lj_long>`
 * :doc:`kspace_style pppm/disp <kspace_style>`
 
+And these pair styles are compatible with the CHARMM force field:
+
+* :doc:`pair_style lj/charmm/coul/charmm <pair_charmm>`
+* :doc:`pair_style lj/charmm/coul/long <pair_charmm>`
+* :doc:`pair_style lj/charmmfsw/coul/long <pair_charmm>`
+
 In LAMMPS the :doc:`fix shake or fix rattle <fix_shake>` command can be
 used to hold the two O-H bonds and the H-O-H angle rigid.  A bond style
 of :doc:`harmonic <bond_harmonic>` and an angle style of :doc:`harmonic
@@ -100,7 +107,9 @@ ignored.
 Below is the code for a LAMMPS input file and a molecule file
 (``tip3p.mol``) of TIP3P water for use with the :doc:`molecule command
 <molecule>` demonstrating how to set up a small bulk water system for
-TIP3P with rigid bonds.
+TIP3P with rigid bonds.  For simplicity and speed the example uses a
+cutoff Coulomb.  Most production simulations require long-range Coulomb
+instead.
 
 .. code-block:: LAMMPS
 

doc/src/Howto_tip4p.rst

@@ -167,7 +167,9 @@ cutoffs are set in the :doc:`pair_style lj/cut/tip4p/long
 Below is the code for a LAMMPS input file using the implicit method and
 the :ref:`TIP3P molecule file <tip3p_molecule>`.  Because the TIP4P
 charges are different from TIP3P they need to be reset (or the molecule
-file changed):
+file changed).  For simplicity and speed the example uses a cutoff
+Coulomb.  Most production simulations require long-range Coulomb
+instead.
 
 .. code-block:: LAMMPS
 

doc/src/Howto_tip5p.rst

@@ -87,7 +87,9 @@ atom style full or use :doc:`fix property/atom mol <fix_property_atom>`
 so that fix rigid/small can identify rigid bodies by their molecule ID.
 Also a :doc:`neigh_modify exclude <neigh_modify>` command is added to
 exclude computing intramolecular non-bonded interactions, since those
-are removed by the rigid fix anyway:
+are removed by the rigid fix anyway.  For simplicity and speed the
+example uses a cutoff Coulomb.  Most production simulations require
+long-range Coulomb instead.
 
 .. code-block:: LAMMPS