Quasi-linear luminescence

A distinctive feature of the O2 and S2 luminescence spectra in minerals is a quasi-linear vibrational structure of the broad luminescence band (Tarash-chan 1978). The O2 and S2 molecular ions are isoelectronic. From the molecular orbital diagram describing their electron structure the emission transition Eg- n l2 is determined. When observing luminescence spectra at 77 K, a fine structure associated with the frequency of intra-molecular vibrations of O2 and S2 is detected. This frequency depends on the type of the molecular ion, on inter-nuclear distance and upon the particular position of the molecular ion in the structures. For S2 the maximum of the emission band lies within the range of 600-700 nm with a mean vibration frequency of 500-600 cm , while for O2 the respective maximum is 450-550 nm with a frequency in the 800-1,200 cm range. 

---