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Undated units conversion factors.

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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@262 f3b2605a-c512-4ea7-a41b-209d697bcdaa
This commit is contained in:
pscrozi
2007-01-30 17:20:42 +00:00
parent a58dbcaa94
commit 973c87562b
3 changed files with 25 additions and 12 deletions
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4
doc/units.html
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@ -30,6 +30,10 @@ and data file, as well as quantities output to the screen, log file,
and dump files. Typically, this command is used at the very beginning and dump files. Typically, this command is used at the very beginning
of an input script. of an input script.
</P> </P>
<P>For real and metallic units, LAMMPS uses physical constants from
www.physics.nist.gov. For the definition of Kcal in real units, LAMMPS
uses the thermochemical calorie = 4.184 J.
</P>
<P>For style <I>lj</I>, all quantities are unitless: <P>For style <I>lj</I>, all quantities are unitless:
</P> </P>
<UL><LI>distance = sigma <UL><LI>distance = sigma

4
doc/units.txt
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@ -27,6 +27,10 @@ and data file, as well as quantities output to the screen, log file,
and dump files. Typically, this command is used at the very beginning and dump files. Typically, this command is used at the very beginning
of an input script. of an input script.
For real and metallic units, LAMMPS uses physical constants from
www.physics.nist.gov. For the definition of Kcal in real units, LAMMPS
uses the thermochemical calorie = 4.184 J.
For style {lj}, all quantities are unitless: For style {lj}, all quantities are unitless:
distance = sigma distance = sigma

27
src/update.cpp
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@ -92,6 +92,11 @@ void Update::init()
void Update::set_units(char *style) void Update::set_units(char *style)
{ {
// physical constants from:
// http://physics.nist.gov/cuu/Constants/Table/allascii.txt
// using thermochemical calorie = 4.184 J
if (strcmp(style,"lj") == 0) { if (strcmp(style,"lj") == 0) {
force->boltz = 1.0; force->boltz = 1.0;
force->mvv2e = 1.0; force->mvv2e = 1.0;
@ -103,21 +108,21 @@ void Update::set_units(char *style)
neighbor->skin = 0.3; neighbor->skin = 0.3;
} else if (strcmp(style,"real") == 0) { } else if (strcmp(style,"real") == 0) {
force->boltz = 0.001987191; force->boltz = 0.0019872067;
force->mvv2e = 48.88821 * 48.88821; force->mvv2e = 48.88821291 * 48.88821291;
force->ftm2v = 1.0 / 48.88821 / 48.88821; force->ftm2v = 1.0 / 48.88821291 / 48.88821291;
force->nktv2p = 68589.796; force->nktv2p = 68568.415;
force->qqr2e = 332.0636; force->qqr2e = 332.06371;
force->qe2f = 23.0602; force->qe2f = 23.060549;
dt = 1.0; dt = 1.0;
neighbor->skin = 2.0; neighbor->skin = 2.0;
} else if (strcmp(style,"metal") == 0) { } else if (strcmp(style,"metal") == 0) {
force->boltz = 8.617e-5; force->boltz = 8.617343e-5;
force->mvv2e = 1.0365e-4; force->mvv2e = 1.0364269e-4;
force->ftm2v = 1 / 1.0365e-4; force->ftm2v = 1 / 1.0364269e-4;
force->nktv2p = 1.602e6; force->nktv2p = 1.6021765e6;
force->qqr2e = 14.40659; force->qqr2e = 14.399645;
force->qe2f = 1.0; force->qe2f = 1.0;
dt = 0.001; dt = 0.001;
neighbor->skin = 2.0; neighbor->skin = 2.0;