Full Q-space analysis of molecular dynamics effect on electron momentum profile of outer-valence orbitals of oxetane

The molecular dynamics effect on electron momentum profiles (EMPs) of outer-valence orbitals of oxetane was investigated theoretically by using the thermal sampling molecular dynamics (TSMD) method to prepare the initial condition of molecules at a certain temperature. A full Q-space sampling is achieved including both harmonic and anharmonic vibrations, particularly the ring-puckering vibration. The sampled conditions were testified by comparing the simulated electron binding spectrum with the photoelectron spectrum. The plane wave impulse approximation (PWIA) is adopted to calculate the EMPs. The results of outer valence orbitals of oxetane are compared with experiments adopting the asymmetric noncoplanar kinematics and theoretical results by ring-puckering model and the harmonic analytical quantum mechanical (HAQM) model. For 3b1 orbital, where the vibrational excitation and anharmonicity of ring-puckering mode cannot be ignored, the present model gives an improved description. For the other orbitals, the present results are similar to the predictions by the HAQM model.