Luminescence nomenclature

In recent years luminescence nomenclature has become confusing within the literature and in practice. Luminescence involves both phosphorescence and fluorescence phenomena. While luminescence is the appropriate term when the specific photochemical mechanism is unknown, fluorescence is far more prevalent in practice. Moreover, the acronym LIE has historically inferred laser -induced fluorescence however, in recent years it has evolved to the more general term light -induced fluorescence due to the various light sources found within laboratory and real-time instruments. Within this chapter fluorescence and LIE are interchangeable terms. 

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The most widely used nomenclature in the field of luminescence of aromatic molecules is that proposed by Birks. 3) The photophysical species and processes in this scheme which are encountered in rigid systems of aryl vinyl polymers are described in Tables 1-4. Triplet excimers have been omitted since it will be shown later that all triplet states play minor roles in the room-temperature, air saturated P2VN blends studied recently 2). 

One of the first studies taking into account rare-earth ions as a pressure sensor by Barnett et al. (1973) used Nd3+ doped into YAIO3. The pressure coefficients dX/dp and temperature coefficients dX/dT were compared there for several potential luminescence sensors up to 10 GPa. As expected, the temperature shift of the R2 Z2 line at 875.3 nm, belonging to the 4F3/2 4L)/2 transitions of Nd3+ (for the nomenclature see, for example, Dieke, 1968),... 

Melmish, W.H., Nomenclature, Symbols, Units and their Usage in Spectrochemical Analysis. VI Molecular Luminescence Spectroscopy, Pure Appl. Chem. 56 (1984) 231-245. 

A very useful paper by Melhuish presents guidance on nomenclature which should be followed in molecular luminescence spectroscopy. General adoption of the recommendations would be useful. 

In contrast to the ultraviolet and visible absorption methods described earlier, details of the methodology of luminescence spectroscopy are not widely known and few standard methods have evolved. Books on theory and techniques are helpful (44) as are memoranda on applications from instrument manufacturers. ASTM Committee E-13.06 on Molecular Luminescence has had large task forces working for several years on practices for instrument testing, nomenclature, and analytical procedures. Recent symposia sponsored by that committee are the basis for two new books (45, 6). 

Part three consists of five chapters in which many of the applications are discussed, viz. lighting (chapter 6), cathode-ray tubes (chapter 7), X-ray phosphors and scintillators (chapters 8 and 9), and several other applications (chapter 10). These chapters discuss the luminescent materials which have been, are or may be used in the applications concerned. Their performance is discussed in terms of the theoretical models presented in earlier chapters. In addition, the principles of the application and the preparation of the materials are dealt with briefly. Appendices on some, often not-well-understood, issues follow (nomenclature, spectral units, literature, emission spectra). 

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