Abstract of Publication No. 371
F. Rodriguez, D.
Hernández and H. U. Güdel
Double excitation (DE) transitions are investigated in NH4MnCl3
microcrystals by high-pressure optical spectroscopy. Two intense bands observed at
39200 and 42200 cm–1 in the UV absorption spectrum at room temperature
are reported for the first time. The bands are assigned to the DE transitions 4T1g
+ 4T1g and 4T1g + 4A1g4Eg
on the basis of their pressure dependence. Apart from
the DE energy as sum of the corresponding single excitation (SE) energies,
the proposed assignment is clearly confirmed through the pressure shift rates.
This procedure enables us to discard any other overlapping SE and DE
transitions as responsible for the observed bands.