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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@922 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp 2007-10-02 23:25:46 +00:00
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2
doc/Section_commands.txt
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@ -592,4 +592,4 @@ description:
These are Kspace solvers contributed by users, which can be used if
"LAMMPS is built with the appropriate package"_Section_start.html#2_3.
"ewald/n"_ewald_n.html :tb(c=4,ea=c,w=100)
"ewald/n"_kspace_style.html :tb(c=4,ea=c,w=100)

46
doc/kspace_style.txt
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@ -12,13 +12,15 @@ kspace_style command :h3
kspace_style style value :pre
style = {none} or {ewald} or {pppm} or others as referenced below :ulb,l
style = {none} or {ewald} or {pppm} or {pppm/tip4p} or {ewald/n} :ulb,l
{none} value = none
{ewald} value = precision
precision = desired accuracy
{pppm} value = precision
precision = desired accuracy
{pppm/tip4p} value = precision
precision = desired accuracy
{ewald/n} value = precision
precision = desired accuracy :pre
:ule
@ -29,12 +31,12 @@ kspace_style none :pre
[Description:]
Define a reciprocal (K-space) solver for LAMMPS to use each timestep
to compute long-range Coulombic interactions. When such a solver is
used in conjunction with an appropriate pair style, the cutoff for
Coulombic interactions is effectively infinite; each charge in the
system interacts with charges in an infinite array of periodic images
of the simulation domain.
Define a K-space solver for LAMMPS to use each timestep to compute
long-range Coulombic interactions or long-range 1/r^N interactions.
When such a solver is used in conjunction with an appropriate pair
style, the cutoff for Coulombic or other 1/r^N interactions is
effectively infinite; each charge in the system interacts with charges
in an infinite array of periodic images of the simulation domain.
The {ewald} style performs a standard Ewald summation as described in
any solid-state physics text.
@ -54,15 +56,21 @@ adds a charge at the massless 4th site in each TIP4P water molecule.
It should be used with "pair styles"_pair_style.html with a
{long/tip4p} in their style name.
There are also additional kspace styles submitted by users which are
included in the LAMMPS distribution. The list of these with links to
the individual styles are given in the kspace section of "this
page"_Section_commands.html#3_5.
The {ewald/n} style augments {ewald} by adding long-range dispersion
sum capabilities for 1/r^N potentials and is useful for simulation of
interfaces "(Veld)"_#Veld. It also performs standard coulombic Ewald
summations, but in a more efficient manner than the {ewald} style.
The 1/r^N capability means that Lennard-Jones or Buckingham potentials
can be used with {ewald/n} without a cutoff, i.e. they become full
long-range potentials.
When a kspace style is used, a pair style that includes the
short-range correction to the pairwise Coulombic forces must also be
selected. These styles are ones that have a {coul/long} in their
style name.
short-range correction to the pairwise Coulombic or other 1/r^N forces
must also be selected. For Coulombic interactions, these styles are
ones that have a {coul/long} in their style name. For Lennard-Jones
or Buckingham interactions, see the "pair_style
lj/coul"_pair_lj_coul.html or "pair_style
buck/coul"_pair_buck_coul.html potentials.
A precision value of 1.0e-4 means one part in 10000. This setting is
used in conjunction with the pairwise cutoff to determine the number
@ -80,13 +88,18 @@ Kspace styles are part of the "kspace" package. They are only enabled
if LAMMPS was built with that package. See the "Making
LAMMPS"_Section_start.html#2_3 section for more info.
The {ewald/n} style is part of the "user-ewaldn" package. It is only
enabled if LAMMPS was built with that package. See the "Making
LAMMPS"_Section_start.html#2_3 section for more info.
When using a long-range pairwise TIP4P potential, you must use kspace
style {pppm/tip4p} and vice versa.
[Related commands:]
"kspace_modify"_kspace_modify.html, "pair_style"_pair_style.html
lj/cut/coul/long, "pair_style"_pair_style.html lj/charmm/coul/long
lj/cut/coul/long, "pair_style"_pair_style.html lj/charmm/coul/long,
"pair_style"_pair_style lj/coul, "pair_style"_pair_style buck/coul
[Default:]
@ -103,3 +116,6 @@ Adam Hilger, NY (1989).
:link(Pollock)
[(Pollock)] Pollock and Glosli, Comp Phys Comm, 95, 93 (1996).
:link(Veld)
[(Veld)] In 't Veld, Ismail, Grest, J Chem Phys, in press (2007).