Quenching rate constants for Ne3P2) metastable atoms at room temperature

Rate constants for quenching of Ne³P₂) metastable atoms have been measured at room temperature by the flowing afterglow technique for 12 reagents; Ar, Kr, Xe, H₂, N₂, CO, HCl, F₂, Cl₂, NF₃, N₂F₄ and N₂O. The values range from ≈5 × 10^?11 cm³ molecule^?1 s^?1 for H₂ and CO up to ≈42 × 10^⊥-11 cm³ molecule^?1s^?1 for Cl₂ and F₂. Comparison with similar data for He(2³S) and Ar(³P₂) suggests that the thermal quenching cross sections follow the trends δ(Ar, ³P₂) > δ(Ne, ³P₂) ? δ(He, 2 ³S). The major exceptions seem to be N₂, CO and Kr which have usually small quenching cross sections for Ar(³P₂).     

Wide energy-window view on the density of states and hole mobility in poly(p-phenylene vinylene)

Using an electrochemically gated transistor, we achieved controlled and reversible doping of poly(p-phenylene vinylene) in a large concentration range. Our data open a wide energy-window view on the density of states (DOS) and show, for the first time, that the core of the DOS function is Gaussian, while the low-energy tail has a more complex structure. The hole mobility increases by more than 4 orders of magnitude when the electrochemical potential is scanned through the DOS.     

NMR evidence for a two-step phase separation in Nd1.85Ce0.15CuO4-delta

By Cu NMR we studied the spin and charge structure in Nd(2-x)Ce(x)CuO(4-delta). For x=0.15, starting from a superconducting sample, the low temperature magnetic order in the sample reoxygenated under 1 bar oxygen at 900 degrees C reveals a peculiar modulation of the internal field, indicative of a phase characterized by large charge droplets ("blob" phase). By prolonged reoxygenation at 4 bars the blobs break up and the spin structure changes to that of an ordered antiferromagnet. We conclude that the superconductivity in the n-type systems competes with a genuine type I Mott-insulating state.