Photoionization cross sections of Ethylene oxide

In this work a theoretical study for photoionization of Ethylene oxide is presented. The photoionization cross section (PICS) for each of the nine valence orbitals and also the summed cross sections are presented. Electronic structure calculations are done to obtain the required molecular properties and the Variational Schwinger method with Pade approximants is used to calculate the PICS. The results are shown in four different approaches: dipole-length/velocity form, static-exchange and static-exchange-polarization levels. The partial PICS for each orbital shows which symmetries of continuum states are responsible for resonance features and how the polarization effects affect the cross sections magnitudes near the threshold. PICS calculations indicate which parent ion state is generated according to the corresponding ionization energies. A correlation is proposed suggesting that the different ionic fragments can be preferentially produced by different electronic states of the parent ion, based on their ionic fragment appearance energies. The summed cross section of all valence orbitals of Ethylene oxide is compared with the results of Acetaldehyde and the analysis suggests that the PICSs, in a given energy range, can be used to identify these isomers. A comparison of our results for EtO and Acetaldehyde with available experimental results for Acetaldehyde and Ethenol demonstrated the the results of three isomers are similar in magnitude in the energy range from 9 to 12 eV. Furthermore, for acetaldehyde, we observed quantitative agreement with the experiment, indicating the reliability of our calculations.