Orientational anisotropy due to molecular field splitting in sulfur 2p photoemission from CS2 and SF6 - theoretical treatment and application to photoelectron recoil
: Kukk, Edwin; Niskanen, Johannes; Travnikova, Oksana; Berholts, Marta; Kooser, Kuno; Peng, Dawei; Ismail, Iyas; Piancastelli, Maria Novella; Püttner, Ralph; Hergerhahn, Uwe; Simon, Marc
Publisher: Royal Society of Chemistry
: 2024
: Physical Chemistry Chemical Physics
: Physical chemistry chemical physics : PCCP
: Phys Chem Chem Phys
: 26
: 32
: 21810
: 21820
: 1463-9076
: 1463-9084
DOI: https://doi.org/10.1039/d4cp01463d
: https://pubs.rsc.org/en/content/articlelanding/2024/cp/d4cp01463d
: https://research.utu.fi/converis/portal/detail/Publication/457443812
Photoelectron recoil strongly modifies the high kinetic energy photoemission spectra from atoms and molecules as well as from surface structures. In most cases studied so far, photoemission from atomic-like inner-shell or core orbitals has been assumed to be isotropic in the molecular frame of reference. However, in the presence of molecular field splitting of p or d orbitals, this assumption is not justified per se. We present a general theoretical treatment, linking the orientational distribution of gas-phase molecules to the electron emission and detection in a certain direction in the laboratory frame. The approach is then applied to the S 2p photoemission from a linear molecule such as CS2 and we investigate, how the predicted orientational anisotropies due to molecular field splitting affect the photoelectron recoil excitations. Lastly, experimental S 2p high-kinetic-energy photoelectron spectra of SF6 and CS2 are analyzed using the modeled recoil lineshapes representing the anisotropy-affected recoil effects.
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EK acknowledges the Research Council of Finland, and MB the Estonian Research Council grant (MOBTP1013) for the financial support.
