| 51 | 
  | 
      DefineOptionalParameterWithDefaultValue(DistanceType, "DistanceType", "sigma"); | 
| 52 | 
  | 
      DefineOptionalParameterWithDefaultValue(EnergyMixingRule, "EnergyMixingRule", "geometric"); | 
| 53 | 
  | 
      DefineOptionalParameterWithDefaultValue(EnergyUnitScaling, "EnergyUnitScaling", 1.0); | 
| 54 | 
+ | 
      DefineOptionalParameterWithDefaultValue(MetallicEnergyUnitScaling, "MetallicEnergyUnitScaling", 1.0); | 
| 55 | 
  | 
      DefineOptionalParameterWithDefaultValue(DistanceUnitScaling, "DistanceUnitScaling", 1.0); | 
| 56 | 
  | 
      DefineOptionalParameterWithDefaultValue(AngleUnitScaling, "AngleUnitScaling", 1.0); | 
| 57 | 
  | 
      DefineOptionalParameterWithDefaultValue(TorsionAngleConvention, "TorsionAngleConvention", "180_is_trans"); |