3
    1 OWE    0.0000000000E+00   0.0000000000E+00   0.0000000000E+00
    2 HWE    0.1000000000E+01   0.0000000000E+00   0.0000000000E+00
    3 HWE    -.3333132476E+00   0.9428161427E+00   0.0000000000E+00

#
#               OWE
#              /   \
#            HWE   HWE
#
#
# Force Field by:
#
# H.J.C. Berendsen, J.R. Grigera, T.P. Straatsma
# J. Phys. Chem., 1987, 91, 6269.
#
# TIP: running the simulation with rigid molecules is faster than using
# constrains. However, if Pakmol is used, a quaternion error is obtain.
# To solve this problem, run a small simulation (e.g. 5 steps) using 
# contrains and then you can switch the force field for rigid molecules.


# Constrain UNITS
CONSTRAINS 1 append
  2        3

ATOM      1  O1                  0.000   0.000   0.000
ATOM      2  H2                  1.000   0.000   0.000
ATOM      3  H3                 -0.333   0.943   0.000