Sensitivity of gas-phase electron diffraction images to the molecular potential parameters

Abstract

Abstract The gas-phase electron diffraction (GED) is a conventional method to extract the geometrical structure and the vibration parameters of molecules. In practice, the mean vibration amplitude is retrieved successfully, while the anharmonicity parameter is usually fixed by a relation with the former. To explicit the reason, we examine the sensitivity of the molecular scattering curve (sM(s)) of N2 molecule to the vibration parameters. The results show that the sM(s) curve is sensitive to the mean vibration amplitude but considerably stable with the changing of the anharmonic parameter even at a high temperature. Besides, many recent studies also focus on the investigation of the laser-induced electron diffraction (LIED) since its high temporal and spatial resolution. However, it is hard to extract the vibration parameters from the LIED data because of the shortage of the analytical form of sM(s) caused by the complicated physical process. So we propose to directly reconstruct the molecular potential instead of extracting the vibration parameters from the LIED. The preliminary purpose is to test the sensitivity of the sM(s) curve to the potential parameters of the Morse potential of N2 considering the nuclear vibration for GED. We demonstrate that the sM(s) curve is sensitive to the change of the potential parameters; thus, the molecular potential can be reconstructed from the GED. This statement is an essential precondition for further investigation of not only the influence of the vibrational effect on the probing of the molecular dissociation but also the reconstruction of the molecular potential from the LIED data.