Merge pull request #1883 from evoyiatzis/master

   * :doc:`coul/long/cs (g) <pair_cs>`

   * :doc:`coul/long/soft (o) <pair_fep_soft>`

   * :doc:`coul/msm (o) <pair_coul>`

   * :doc:`coul/slater/cut <pair_coul_slater>`

   * :doc:`coul/slater/long <pair_coul_slater>`   

   * :doc:`coul/shield <pair_coul_shield>`

   * :doc:`coul/streitz <pair_coul>`

   * :doc:`coul/wolf (ko) <pair_coul>`

.. 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}}{\lambda} exp\left( -2r_{ij}/\lambda \right) \right) \right)                       \qquad r < r_c 

where :math:`r_c` is the cutoff distance and :math:`\lambda` 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)** Gonzalez-Melchor, Mayoral, Velázquez, and Alejandre, J Chem Phys, 125, 224107 (2006).

.. _Vaiwala:

**(Vaiwala)** Vaiwala, Jadhav, and Thaokar, J Chem Phys, 146, 124904 (2017).

gneb

GNEB

Goldfarb

Gonzalez-Melchor

googlemail

Gordan

GPa

izz

Izz

Jacobsen

Jadhav

jagreat

Jalalvand

james

Maxwellian

maxX

Mayergoyz

Mayoral

mbt

Mbytes

MBytes

Mees

Mehl

Mei

Melchor

Meloni

Melrose

Mem

polybond

polydisperse

polydispersity

polyelectrolyte

polyhedra

popen

Popov

supersphere

Supinski

Surblys

surfactant

surfactants

Suter

Sutmann

tfMC

th

Thakkar

Thaokar

thb

thei

Theodorou

Uzdin

vacf

Vaid

Vaiwala

valent

Valeriu

valgrind

vectorized

Vegt

vel

Velázquez

Verlag

verlet

Verlet