Symmetry breaking in core-valence double photoionization of SO2

Abstract

Core-valence double photoionization electron spectra of the SO 2 molecule involving the S 2p and O 1s inner shells have been measured using a time-of-flight multiparticle coincidence technique. The experimental spectra are compared with quantum-chemical calculations based on density functional theory by which several core-valence dicationic states are identified. Assignments conform with a picture where the formation of a O 1s-valence dicationic state is associated with a physical, "pseudo-Jahn-Teller," symmetry breaking and core-hole localization. It is shown that while density functional theory gives very good transition energies in the symmetry-broken case, it gives a poor representation in the symmetry-restricted case, and an incomplete account of the Hartree-Fock localization energy.

Quantum Mechanics/Molecular Mechanics Modeling of Photoelectron Spectra: The Carbon 1s Core–Electron Binding Energies of Ethanol–Water Solutions

“…This open-shell DFT method allows for a full second order optimization and full orbital relaxation and has earlier also been used in ab initio single or multiconfiguration expanded wave functions. For recent work on such core-hole calculations, we refer to refs and . The effect of charge transfer and the explicit effects of hydrogen bonding were studied by extending the QM region to cover the first solvation shell of the molecules around the central ethanol.…”

Single-photon multiple ionization forming double vacancies in the2psubshell of argon

“…In the past decade the PES coincidence techniques have been applied to SPDI processes involving core vacancies. Core-valence ionization, where one electron is emitted from a (deep) inner shell and one from the valence, has been studied for a range of inner shells and targets [6][7][8][9][10][11][12]. Very recently, SPDI leading to atoms and molecules with two vacancies in the core, so-called double core holes (DCH), have been added to the list [13][14][15][16][17].…”

Single-photon double and triple ionization of acetaldehyde (ethanal) studied by multi-electron coincidence spectroscopy

“…Double photoionization electron coincidence spectroscopy based on a magnetic bottle introduced by Eland et al 10 in 2003 opened up the possibility to determine the correlation of electrons with a wide range of kinetic energies. To begin with, this method was used to study valence double ionization of atoms and molecules [10][11][12][13][14][15][16][17][18][19] using a pulsed He lamp, and was subsequently applied to studies of core-valence double photoionization of atoms and molecules [20][21][22][23][24][25][26] utilizing synchrotron radiation sources. Both processes are examples of double ionization, where the two electrons emitted may share the excess energy provided by the absorbed photon arbitrarily, in contrast to fixed electron kinetic energies typically observed in cases of single core shell ionization followed by normal Auger decay.…”