ABSTRACT
The emission and absorption spectra measured by Lehmann are all for room temperature and for the activator concentrations shown. These concentrations are close to, but not necessarily at the optimum in every case. The absorption spectra indicate where the materials may be excited (no absorption-no emission). Too few excitation spectra were available to be included. All spectra are plotted on a quantum basis; that is, the abscissa is calibrated in electron volts (eV) rather than wavelength units because luminescence processes are quantum processes. It is also easier to compare the widths of approximately Gaussian-shaped emission bands plotted in eV than it is to compare the widths of very nonGaussian-shaped bands plotted in wavelength units. The simple conversion between wavelength (in nanometers, nm) and quantum energy (in eV) is
(nm) = 1240/(eV) Using this conversion, the two optical wavelengths used for excitation correspond to:
365 nm — 3.40 eV 254 nm — 4.88 eV
Only the main references to original publications are given. Absence of a reference means that none is known.
