REFRACTIVE-INDEX EFFECT ON SPECTRAL TRANSMISSION FACTOR OF LIQUIDS ONDOUBLE-BEAM MOLECULAR ABSORPTION SPECTROMETRY

The spectral transmission fatter of liquids is currently determined by spectrophotometry for various applications, including spectrocolorime try. Applications exist that require an accuracy of the order of 10(-3 ) or higher in the intrinsic transmission factor. This requirement bri ngs about the exploration of the corrections made necessary by the mea suring cells' lack of pairing, the reference liquid's (water or solven t) spectral nonflatness, the refractive-index difference between the s ample and the reference liquid, and the multiple reflections on cell w alls. An analysis is conducted, and a procedure is presented for the s elf-correction of the cell's lack of pairing and for the correction of systematic errors from the reference liquid's spectral nonflatness as well as for the refractive-index discrepancies between the sample and the reference liquids and for the multiple beam reflections. (C) 1998 Optical Society of America.