The density functional theory (DFF)/B3LYP at 6-3l1＋G(2d) level was used to study the equilibrium geometry, dipole moment, energy levels, HOMO-LUMO gap and potential energy curve of B2 ground state molecule under different direction electric field ranging from 0 to ＋0.02 a.u. The results show that the bond length and dipole moment increased, but the system energy, energy levels and intermolecular potential decreased with increasing the different direction field. The energy gap was associated with the direction of electric field, which was decreasing with the increase of electric field parallel to molecular axis but increased with the increase of external field perpendicular to the molecular axis. The influence on intermolecular potential was incrementing with the increment of internuclear distance under electric field parallel to the molecular axis. The intrinsic “platform for potential energy” was destroyed.

Key words: B2, density functional theory (DFF), electric field