Cross sections and photoelectron angular distributions in photodetachmentfrom negative ions using equation-of-motion coupled-cluster Dysonorbitals

摘要

We report total and differential cross sections for photodetachment from negative ions using Dysonorbitals calculated from equation-of-motion coupled-cluster wave functions and free wavedescription of the detached electron. The energy dependence of the cross sections is reproducedwell, however, the accuracy of absolute values varies. For F~-, C~-, NH_2~-, and H~-, the calculated crosssections are within the error bars from the experimental values, whereas the errors for Li~- and OH-are about 20%. The largest errors are observed for O~- and O_2~- for which the calculated cross sectionsdiffer from the experimental ones by factors of 3 and 2, respectively. Calculated anisotropyparameters for atomic anions exhibit too slow decrease, which suggests that the diffuseness of thecomputed Dyson orbitals is underestimated. Moreover, in the asymptotic region, the orbitals exhibitartifactual oscillations probably due to the limitations of Gaussian basis sets. The analysis of thetrends in the experimental anisotropy parameters suggests that the interaction of the detachedelectron with the core, which is neglected in the present model, is important.