OH absorption coefficients of rutile and cassiterite deduced from nuclear reaction analysis and FTIR spectroscopy

The OH content of four rutile and two cassiterite single-crystals was studi ed by nuclear reaction analysis (NRA) and by polarised FTIR microspectrosco py. The OH absorption bands of both minerals are centered around 3300cm(-1) with different absorption features. The analytical H2O content determined by NRA ranges from 70 to 820 wt.ppm. The integrated molar absorption coeffi cients deduced from the total integrated OH absorbances are equal to 38000 l.mol(H2O)(-1).cm(-2) for rutile and 65000 l.mol(H2O)(-1).cm(-2) for cassit erite. For both minerals the absorption coefficients are significantly smal ler than those expected from the linear calibration curves given by Paterso n (1982) and by Libowitzky and Rossman (1997).