defined for each wavenumber value of the two spectra. If the background spectrum B closely represents
the response of the FTIR system to a transparent sample, then the percent transmittance closely
approximates the percentage of the infrared radiation transmitted by the sample (represented by the
spectrum S). Because water is the only absorbing compound present in the single-beam spectrum B,
the spectrum transmittance (shown in Figure C5) closely approximates the percent transmittance
spectrum of water.