13 research outputs found
Spin singlet small bipolarons in Nb-doped BaTiO3
The magnetic susceptibility and electrical resistivity of n-type
BaTi{1-x}Nb{x}O3 have been measured over a wide temperature range. It is found
that, for 0 < x < 0.2, dopant electrons form immobile spin singlet small
bipolarons with binding energy around 110 meV. For x = 0.2, a maximum in the
electrical resistivity around 15 K indicates a crossover from band to hopping
transport of the charge carriers, a phenomenon expected but rarely observed in
real polaronic systems.Comment: 5 pages, 4 figure
Photodissociation and photochemistry of V⁺ (H₂O)n, n = 1–4, in the 360–680 nm region
The photodissociation and photochemistry of V⁺ (H₂O)n, n = 1–4, was studied in the 360–680 nm region in
a Fourier transform ion cyclotron resonance mass spectrometer. The light of a high pressure mercury arc lamp was
filtered with band pass filters, with center wavelengths from 360 to 680 nm in steps of 20 nm. The bandwidth of
the filters, defined as full width at half maximum, was 10 nm. Photodissociation channels are loss of water molecules,
as well as loss of atomic or molecular hydrogen, which may be accompanied by loss of water molecules.
The most intense absorptions are red shifted with increasing hydration. Theoretical spectra are calculated with
time dependent density functional theory. Calculations reproduce all features of the experimental spectra, including
the red shift with increasing hydration shell and the overall pattern of strong and weak absorptions