Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals

Abstract

We report total and differential cross sections for photodetachment from negative ions using Dyson orbitals calculated from equation-of-motion coupled-cluster wave functions and free wave description of the detached electron. The energy dependence of the cross sections is reproduced well, however, the accuracy of absolute values varies. For F(-), C(-), NH(2)(-), and H(-), the calculated cross sections 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 sections differ from the experimental ones by factors of 3 and 2, respectively. Calculated anisotropy parameters for atomic anions exhibit too slow decrease, which suggests that the diffuseness of the computed Dyson orbitals is underestimated. Moreover, in the asymptotic region, the orbitals exhibit artifactual oscillations probably due to the limitations of Gaussian basis sets. The analysis of the trends in the experimental anisotropy parameters suggests that the interaction of the detached electron with the core, which is neglected in the present model, is important.

Isomer-specific vibronic structure of the 9-, 1-, and 2-anthracenyl radicals via slow photoelectron velocity-map imaging

“…Our electronic structure calculations indicate that the ground state of each neutral radical is accessed by removing an electron from an in-plane σ molecular orbital (MO) with s-p character localized on the deprotonated site of the closed-shell anion, whereas the first excited state of each radical is accessed by removal of an electron from a delocalized π MO of the anion. Calculated Dyson orbitals (38) for the photodetachment transitions for each isomer are shown in Fig. 4.…”

“…The photoelectron angular distributions and photodetachment cross sections for transitions to the neutral ground and excited states were calculated as functions of eKE with the ezDyson program (38,65). ezDyson takes as input the ab initio Dyson orbitals for the relevant photodetachment transitions and finds the contribution of partial spherical waves with angular momentum l ≤ 4 to the wavefunction of the outgoing photoelectron.…”

Anion Resonances of para-Benzoquinone Probed by Frequency-Resolved Photoelectron Imaging

“…53,54 In principle, PADs can be calculated using, for example, the relevant Dyson orbitals. 61,62 However, when autodetachment occurs from resonances and interference can occur with direct detachment channels, these methods become more difficult to apply and additional development on the theoretical front is required to capture changes in the PADs.…”

Vibronic coupling in the superoxide anion: The vibrational dependence of the photoelectron angular distribution

“…54 More recent treatments of O 2 − photodetachment include single and multichannel scattering calculations using Schwinger variational methods 55 and calculation of the radial matrix elements for the central-potential model of Cooper and Zare using Dyson orbitals computed via coupled-cluster equation of motion methods. 56 Only in the application of the ZCC model 57 to diatomic anion photodetachment has the effect of vibrational excitation on the angular distribution been quantified. 2 The systematic test of the predicted ␤͑E͒ trends for each vibronic transition associated with the O 2 ͑X …”