9 research outputs found
Non-jellium scaling of metal cluster ionization energies and electron affinities
Experimental literature data on ionization energies and electron affinities
of metal clusters are reviewed and analyzed in terms of
an expansion in the inverse cluster radius. The coefficient of the finite size correction
for ionization energies decreases with increasing bulk work function
whereas the corresponding coefficient for electron affinities increases.
This sharply contrasts the predictions based both on
density functional theory of spherical jellium clusters and on classical electrostatics.
A scaling of the coefficient for the ionization potentials
with the atomic radius yields a linear behavior which extrapolates to zero around 6Â eV
Effect of Intensive Weight Loss Programs on Diabetes Remission in Newly Diagnosed Patients with Type 2 Diabetes: A Systematic Review
International audienc
Cations Strongly Reduce Electron Hopping Rates in Aqueous Solutions
We study how the ultrafast intermolecular hopping of electrons excited from the water O1s core level into unoccupied orbitals depends on the local molecular environment in liquid water. Our probe is the resonant Auger decay of the water O1s core hole (lifetime similar to 3.6 fs), by which we show that the electron-hopping rate can be significantly reduced when a first-shell water molecule is replaced by an atomic ion. Decays resulting from excitations at the O1s post-edge feature (similar to 540 eV) of 6 m LiBr and 3 m MgBr2 aqueous solutions reveal electron-hopping times of similar to 1.5 and 1.9 fs, respectively; the latter represents a 4-fold increase compared to the corresponding value in neat water. The slower electron-hopping in electrolytes, which shows a strong dependence on the charge of the cations, can be explained by ion-induced reduction of water-water orbital mixing. Density functional theory electronic structure calculations of solvation geometries obtained from molecular dynamics simulations reveal that this phenomenon largely arises from electrostatic perturbations of the solvating water molecules by the solvated ions. Our results demonstrate that it is possible to deliberately manipulate the rate of charge transfer via electron-hopping in aqueous media
High resolution multiphoton spectroscopy by a tunable free-electron-laser light
Seeded free electron lasers theoretically have the intensity, tunability, and resolution required for multiphoton spectroscopy of atomic and molecular species. Using the seeded free electron laser FERMI and a novel detection scheme, we have revealed the two-photon excitation spectra of dipole-forbidden doubly excited states in helium. The spectral profiles of the lowest (-1,0)^{+1} ^{1}S^{e} and (0,1)^{0} ^{1}D^{e} resonances display energy shifts in the meV range that depend on the pulse intensity. The results are explained by an effective two-level model based on calculated Rabi frequencies and decay rates