constant:	energy_offset=0.;
harmonic_angle:	particle_type1=8,	particle_type2=1,	particle_type3=1,	spring_constant=1.,	equilibrium_distance=1.;
morse:	particle_type1=1,	particle_type2=1,	spring_constant=1.,	equilibrium_distance=1.,	dissociation_energy=0.1;
morse:	particle_type1=8,	particle_type2=1,	spring_constant=1.,	equilibrium_distance=1.,	dissociation_energy=0.1;