Optical Absorption and EPR Studies on Enargite

The behaviour of transition metal ions in enargite has been studied by electron paramagnetic resonance and absorption spectroscopy in the UV–VIS and near-IR regions. The ground state of Cu(II) ions in enargite is confirmed as 2B1g since g11>g⊥ (2.54>2.11). Three characteristic bands observed in the optical absorption spectra at 8275, 13105 and 18420 cm−1 are assigned to the transitions, 2B1g→2A1g, 2B1g→2B2 and 2B1g→2Eg, respectively, of Cu(II) ion in the tetragonal field. The presence of Fe(II) bands is an evidence for iron impurities in the mineral