<s>
The	O
OPLS	B-Algorithm
(	O
Optimized	O
Potentials	O
for	O
Liquid	O
Simulations	O
)	O
force	O
field	O
was	O
developed	O
by	O
Prof	O
.	O
William	O
L	O
.	O
Jorgensen	O
at	O
Purdue	O
University	O
and	O
later	O
at	O
Yale	O
University	O
.	O
</s>
<s>
The	O
functional	O
form	O
of	O
the	O
OPLS	B-Algorithm
force	O
field	O
is	O
very	O
similar	O
to	O
that	O
of	O
AMBER	B-Device
:	O
</s>
<s>
Several	O
sets	O
of	O
OPLS	B-Algorithm
parameters	O
have	O
been	O
published	O
.	O
</s>
<s>
There	O
is	O
OPLS-ua	O
(	O
united	O
atom	O
)	O
,	O
which	O
includes	O
hydrogen	O
atoms	O
next	O
to	O
carbon	O
implicitly	O
in	O
the	O
carbon	O
parameters	O
,	O
and	O
can	O
be	O
used	O
to	O
save	O
simulation	O
time	O
.	O
</s>
<s>
OPLS-aa	O
(	O
all	O
atom	O
)	O
includes	O
every	O
atom	O
explicitly	O
.	O
</s>
<s>
OPLS	B-Algorithm
simulations	O
in	O
aqueous	O
solution	O
typically	O
use	O
the	O
TIP4P	O
or	O
TIP3P	O
water	O
model	O
.	O
</s>
<s>
A	O
distinctive	O
feature	O
of	O
the	O
OPLS	B-Algorithm
parameters	O
is	O
that	O
they	O
were	O
optimized	O
to	O
fit	O
experimental	O
properties	O
of	O
liquids	O
,	O
such	O
as	O
density	O
and	O
heat	O
of	O
vaporization	O
,	O
in	O
addition	O
to	O
fitting	O
gas-phase	O
torsional	O
profiles	O
.	O
</s>
<s>
The	O
reference	O
implementations	O
of	O
the	O
OPLS	B-Algorithm
force	O
field	O
are	O
the	O
BOSS	B-Application
and	O
MCPRO	O
programs	O
developed	O
by	O
Jorgensen	O
.	O
</s>
<s>
Other	O
packages	O
such	O
as	O
TINKER	B-Application
,	O
GROMACS	B-Application
,	O
PCMODEL	O
,	O
Abalone	B-Application
,	O
LAMMPS	B-Application
,	O
Desmond	O
and	O
NAMD	B-Application
also	O
implement	O
OPLS	B-Algorithm
force	O
fields	O
.	O
</s>
