Biography:

In the past E. Shigemasa has collaborated on articles with Y. Hikosaka and F. Penent. One of their most recent publications is Angular distribution of photoelectrons from fixed-in-space molecules. Which was published in journal Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms.

More information about E. Shigemasa research including statistics on their citations can be found on their Copernicus Academic profile page.

E. Shigemasa's Articles: (5)

Angular distribution of photoelectrons from fixed-in-space molecules

AbstractAngular distributions of 1sσ photoelectrons from spatially fixed N2 molecules have been measured around the σ∗ shape resonance in the K-shell continuum. This has been realized with the use of a coincidence technique: by detecting the photoelectron in coincidence with the fragment ion having the information on the molecular orientation at a moment of photoabsorption. The angular distributions obtained by this technique are rich in structure, which are completely different from usual photoelectron angular distributions from randomly oriented molecules. The orbital angular momentum properties of the 1sσ photoelectrons at the σ∗ shape resonance have been revealed.

Site-specific formation of metastable dications following inner-shell ionization of CO2

Highlights•Site-specific formation of metastable dications in the C1s and O1s Auger decay of CO2.•Sole contribution in the metastable formation from the 1πg−2 states.•Site-specificity led by the charge distribution of the 1πg orbital.

Ion pair formation in the vacuum ultraviolet region of NO studied by negative ion imaging spectroscopy

AbstractThe pair formation of positive and negative fragment ions has been studied in the vacuum ultraviolet region of NO, with negative ion imaging spectroscopy. The negative ion yield curve obtained in the photon energy region of 19–25 eV exhibits many structures which are absent from the photoabsorption spectrum in the same region. The partial yields and asymmetry parameters associated with the dissociations into individual ion pair limits have been extracted from the negative ion images observed. On the basis of these quantities, the assignments for the structures exhibited on the negative ion yield curve are given and the dynamical properties on the ion pair dissociation are discussed.

Photoelectron recapture through post-collision interaction in N2

AbstractPhotoelectron spectroscopy has been applied to investigate electron emissions from excited atomic fragments in the vicinity of the K-shell ionization threshold of N2. It is found that low kinetic energy electrons are emitted in the photon energy region both immediately below and above the K-shell ionization threshold. The electron emissions are attributable to autoionization from the excited fragments in low-n Rydberg states. The N2+* states leading to the formation of the excited fragments which autoionize with emitting slow electrons, are populated not only by spectator Auger decay from the core-excited states, but also by the recapture of slow photoelectrons into the Rydberg orbitals.

Molecular single photon double K-shell ionization

AbstractWe have studied single photon double K-shell ionization of small molecules (N2, CO, C2H2n (n = 1–3), …) and the Auger decay of the resulting double core hole (DCH) molecular ions thanks to multi-electron coincidence spectroscopy using a magnetic bottle time-of-flight spectrometer. The relative cross-sections for single-site (K−2) and two-site (K−1K−1) double K-shell ionization with respect to single K-shell (K−1) ionization have been measured that gives important information on the mechanisms of single photon double ionization. The spectroscopy of two-site (K−1K−1) DCH states in the C2H2n (n = 1–3) series shows important chemical shifts due to a strong dependence on the CC bond length. In addition, the complete cascade Auger decay following single site (K−2) ionization has been obtained.

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