Abstract: With density functional B3P86 method and cc-PV5Z base,bond lengths,dipole moments,vibration frequencies and other physical parameters of BH molecule in external electric fields are obtained.With analysis of physical parameter,scope of dissociation field is determined,appropriate parameters to scan single point energies are set,and potential energy curves are obtained.It shows physical parameters and potential energies in external electric fields,especially in reverse electric fields.Potential energy function without electric field is fitted by Morse potential.Fitting parameters are in good agreement with experiment.Potential energy under external electric fields is fitted using a potential model,which is constructed with dipole approximation.Critical electric parameters are calculated.They are consistent with other numerical results,so the model is reliable and accurate.It provides theoretical reference for molecular spectroscopy,dynamics and cooling with Stark effect.

Key words: BH molecule, potential function model, external electric field