<s>
Ghemical	B-Language
is	O
a	O
computational	O
chemistry	O
software	O
package	O
written	O
in	O
C++	B-Language
and	O
released	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
The	O
program	O
has	O
graphical	B-Application
user	I-Application
interface	I-Application
based	O
on	O
GTK+2	B-Application
and	O
supports	O
quantum	O
mechanical	O
and	O
molecular	O
mechanic	O
models	O
,	O
with	O
geometry	O
optimization	O
,	O
molecular	O
dynamics	O
,	O
and	O
a	O
large	O
set	O
of	O
visualization	O
tools	O
.	O
</s>
<s>
Ghemical	B-Language
relies	O
on	O
external	O
code	O
to	O
provide	O
the	O
quantum-mechanical	O
calculations	O
—	O
MOPAC	B-Application
provides	O
the	O
semi-empirical	O
MNDO	O
,	O
MINDO	O
,	O
AM1	O
,	O
and	O
PM3	O
methods	O
,	O
and	O
MPQC	B-Language
methods	O
based	O
on	O
Hartree	O
–	O
Fock	O
calculations	O
.	O
</s>
<s>
The	O
chemical	O
expert	B-Application
system	I-Application
is	O
based	O
on	O
OpenBabel	B-Application
,	O
which	O
provides	O
basis	O
functionality	O
like	O
atom	O
typing	O
,	O
rotamer	O
generation	O
and	O
import/export	O
of	O
chemical	O
file	O
formats	O
.	O
</s>
