documentation file for the coul/slater styles

pair_coul_slater.rst

@@ -0,0 +1,121 @@
+.. index:: pair_style coul/slater
+
+pair_style coul/slater/cut command
+============================
+
+pair_style coul/slater/long command
+================================
+
+Syntax
+""""""
+
+
+.. code-block:: LAMMPS
+
+   pair_style coul/slater/cut lamda cutoff
+   pair_style coul/slater/long lamda cutoff
+
+lamda = decay length of the charge (distance units)
+cutoff = cutoff (distance units)
+
+Examples
+""""""""
+
+
+.. code-block:: LAMMPS
+
+   pair_style coul/slater/cut 1.0 3.5
+   pair_coeff * *
+   pair_coeff 2 2 2.5
+
+   pair_style coul/slater/long 1.0 12.0
+   pair_coeff * *
+   pair_coeff 1 1 5.0
+
+Description
+"""""""""""
+
+Styles *coul/slater* compute electrostatic interactions in mesoscopic models
+which employ potentials without explicit excluded-volume interactions. 
+The goal is to prevent artificial ionic pair formation by including a charge 
+distribution in the Coulomb potential, following the formulation of 
+:ref:`(Melchor) <Melchor>`: 
+
+.. math::
+
+   E  = & \frac{Cq_iq_j}{\epsilon r} \left( 1- \left( 1 + \frac{r_{ij}}{\lamda} exp\left( -2r_{ij}/\lamda \right) \right) \right)                       \qquad r < r_c 
+
+
+where :math:`r_c` is the cutoff distance and :math:`\lamda` is the decay length of the charge.
+C is the same Coulomb conversion factor as in the pair\_styles coul/cut and coul/long. In this way the Coulomb
+interaction between ions is corrected at small distances r. 
+For the *coul/slater/cut* style, the potential energy for distances larger than the cutoff is zero, 
+while for the *coul/slater/long*, the long-range interactions are computed either by the Ewald or the PPPM technique.
+
+Phenomena that can be captured at a mesoscopic level using this type of electrostatic 
+interactions include the formation of polyelectrolyte-surfactant aggregates, 
+charge stabilization of colloidal suspensions, and the formation of
+complexes driven by charged species in biological systems. :ref:`(Vaiwala) <Vaiwala>`.
+
+The cutoff distance is optional. If it is not used,
+the default global value specified in the pair_style command is used.
+For each pair of atom types, a specific cutoff distance can be defined via the :doc:`pair_coeff <pair_coeff>` command as in the example
+above, or in the data file or restart files read by the
+:doc:`read_data <read_data>` or :doc:`read_restart <read_restart>`
+commands:
+
+* :math:`\r_c` (distance units)
+
+The global decay length of the charge (:math:`\lambda`) specified in the pair\_style command is used for all pairs.
+
+
+----------
+
+
+**Mixing, shift, table, tail correction, restart, rRESPA info**\ :
+
+For atom type pairs I,J and I != J, the cutoff distance for the
+*coul/slater* styles can be mixed.  The default mix value is *geometric*\ .
+See the "pair\_modify" command for details.
+
+The :doc:`pair_modify <pair_modify>` shift and table options are not relevant
+for these pair styles.
+
+These pair styles do not support the :doc:`pair_modify <pair_modify>`
+tail option for adding long-range tail corrections to energy and
+pressure.
+
+These pair styles write their information to :doc:`binary restart files <restart>`, so pair\_style and pair\_coeff commands do not need
+to be specified in an input script that reads a restart file.
+
+This pair style can only be used via the *pair* keyword of the
+:doc:`run_style respa <run_style>` command.  It does not support the
+*inner*\ , *middle*\ , *outer* keywords.
+
+Restrictions
+""""""""""""
+
+The  *coul/slater/long* style requires the long-range solvers included in the KSPACE package. 
+
+These styles are part of the "USER-MISC" package.  They are only enabled if
+LAMMPS was built with that package.  See the :doc:`Build package <Build_package>` doc page for more info.
+
+Related commands
+""""""""""""""""
+
+:doc:`pair_coeff <pair_coeff>`, :doc:`pair_style, hybrid/overlay <pair_hybrid>`, :doc:`kspace_style <kspace_style>`
+
+**Default:** none
+
+----------
+
+
+.. _Melchor:
+
+**(Melchor)** González-Melchor, Mayoral, Velázquez, and Alejandre, J Chem Phys, 125, 224107 (2006).
+
+.. _Vaiwala:
+
+**(Vaiwala)** Vaiwala, Jadhav, and Thaokar, J Chem Phys, 146, 124904 (2017).
+
+