2 research outputs found
Electron Spectroscopy and Density-Functional Study of "Ferric Wheel" Molecules
The Li-centered "ferric wheel" molecules with six oxo-bridged iron atoms form
molecular crystals. We probed their electronic structure by X-ray photoelectron
(XPS) and soft X-ray emission spectroscopy (XES), having calculated in parallel
the electronic structure of a single "ferric wheel" molecule from
first-principles by tools of the density-functional theory, using,
specifically, the Siesta method. The Fe local moments were found to be 4 mu_B,
irrespective of their mutual orientation. Neighbouring atoms, primarily oxygen,
exhibit a noticeable magnetic polarization, yielding effective spin S=5/2 per
iron atom, that can get inverted as a "rigid" one in magnetic transitions.
Corresponding energy preferences can be mapped onto the Heisenberg model with
effective exchange parameter J of about -80 K.Comment: 8 pages with 3 embedded postscript figures; uses elsart.cls;
contribution at the E-MRS 2003 Spring Meeting (Strasbourg, June 2003
Resonant inelastic x-ray scattering at the N2 π*-resonance: Lifetime-vibrational interference, radiative electron rearrangement, and wave-function imaging
Resonant inelastic x-ray scattering spectra excited at the pi*-resonance of the nitrogen molecule are presented. Well-resolved vibrational excitations in the electronic ground state, and in the 3 sigma g(-1 )1 pi(1)(g) a(1) Pi(g) state are observed. The spectra are analyzed within the Kramers-Heisenberg formalism, and the importance of lifetime-vibrational interference effects is highlighted. In addition, strongly dissociative multiply excited final states populated in radiative electron rearrangement are found in the valence ionization continua. The vibrational wave functions of the core-excited state are imaged on the strongly dissociative final state potentials