The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c mT-m0 4.0 GeV/c. ...The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system.
We will provide a method to place the levels of all trivalent lanthanides with respect to the top of the valence band and bottom of the conduction band in oxides containing transition metal ...complexes. The method will be applied to CaTiO
3, YVO
4, LaVO
4, CaNb
2O
6, YNbO
4, CaWO
4, YTaO
4, and LaTaO
4, but in principle can be applied to any oxide containing transition metal complexes with lanthanide dopants on either rare earth or alkaline earth sites. Crucial to place the energy levels is the energy for intervalence charge transfer between a lanthanide (
Pr
3
+
and
Tb
3
+
) and a transition metal ion (
Ti
4
+
,
V
5
+
,
Nb
5
+
,
Mo
6
+
,
Ta
5
+
,
W
6
+
) that can be observed in luminescence excitation spectra. The quenching of
Pr
3
+
emission from the
3
P
0
state and of
Tb
3
+
emission from the
5
D
3
and
5
D
4
states provides complementary information.
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