<s>
Bond	B-Algorithm
order	I-Algorithm
potential	I-Algorithm
is	O
a	O
class	O
of	O
empirical	O
(	O
analytical	O
)	O
interatomic	O
potentials	O
which	O
is	O
used	O
in	O
molecular	O
dynamics	O
and	O
molecular	O
statics	O
simulations	O
.	O
</s>
<s>
Examples	O
include	O
the	O
Tersoff	B-Algorithm
potential	I-Algorithm
,	O
the	O
EDIP	O
potential	B-Algorithm
,	O
the	O
Brenner	B-Algorithm
potential	I-Algorithm
,	O
the	O
Finnis	O
–	O
Sinclair	O
potentials	O
,	O
</s>
<s>
ReaxFF	B-Algorithm
,	O
</s>
<s>
They	O
have	O
the	O
advantage	O
over	O
conventional	O
molecular	O
mechanics	O
force	O
fields	O
in	O
that	O
they	O
can	O
,	O
with	O
the	O
same	O
parameters	O
,	O
describe	O
several	O
different	O
bonding	O
states	O
of	O
an	O
atom	B-Language
,	O
and	O
thus	O
to	O
some	O
extent	O
may	O
be	O
able	O
to	O
describe	O
chemical	O
reactions	O
correctly	O
.	O
</s>
<s>
This	O
means	O
that	O
the	O
potential	B-Algorithm
is	O
written	O
as	O
a	O
simple	O
pair	O
potential	B-Algorithm
depending	O
on	O
the	O
distance	O
between	O
two	O
atoms	O
,	O
but	O
the	O
strength	O
of	O
this	O
bond	O
is	O
modified	O
by	O
the	O
environment	O
of	O
the	O
atom	B-Language
via	O
the	O
bond	O
order	O
.	O
</s>
<s>
is	O
a	O
function	O
that	O
in	O
Tersoff-type	O
potentials	O
depends	O
inversely	O
on	O
the	O
number	O
of	O
bonds	O
to	O
the	O
atom	B-Language
,	O
the	O
bond	O
angles	O
between	O
sets	O
of	O
three	O
atoms	O
,	O
and	O
optionally	O
on	O
the	O
relative	O
bond	O
lengths	O
,	O
.	O
</s>
<s>
The	O
other	O
limiting	O
case	O
,	O
for	O
increasingly	O
many	O
number	O
of	O
bonds	O
within	O
some	O
interaction	O
range	O
,	O
and	O
the	O
potential	B-Algorithm
turns	O
completely	O
repulsive	O
(	O
as	O
illustrated	O
in	O
the	O
figure	O
to	O
the	O
right	O
)	O
.	O
</s>
<s>
where	O
is	O
the	O
electron	O
density	O
at	O
the	O
location	O
of	O
atom	B-Language
.	O
</s>
<s>
The	O
original	O
bond	B-Algorithm
order	I-Algorithm
potential	I-Algorithm
concept	O
has	O
been	O
developed	O
further	O
to	O
include	O
distinct	O
bond	O
orders	O
for	O
sigma	O
bonds	O
and	O
pi	O
bonds	O
in	O
the	O
so-called	O
BOP	O
potentials	O
.	O
</s>
<s>
Also	O
the	O
ReaxFF	B-Algorithm
potential	B-Algorithm
can	O
be	O
considered	O
a	O
bond	B-Algorithm
order	I-Algorithm
potential	I-Algorithm
,	O
although	O
the	O
motivation	O
of	O
its	O
bond	O
order	O
terms	O
is	O
different	O
from	O
that	O
described	O
here	O
.	O
</s>
