Abstract: We obtained the ground states geometry, dipole moment and total energy of C₅H₈O under different intense electric fields rangin g from -0.006 to 0.006 by using density functional theory DFT/B3P86 at the 6-3 11++G(-d,p-) basis set level. The calculation results show that the geomet ric configuration of C₅H₈O molecule is affected by the electric field intensity . The dipole moment of the molecule increases with the increase of electric fiel d intensity. The total energy of the molecule is -271.481 6 as F=0. The tota l energy of the molecule decreases with the increase of the electric field intensity. The total energy of the molecule reaches the maximum -27 1.475 2 as F=-0.006. The total energy of the system decreases with the incre ase of the electric field intensity.

Key words: Raman spectrum, cyclopentanone, structure, property, external electric field