Absorption Spectra of Nitrobenzene Measured With Incoherent White-Light Excitation

摘要

We report on the photo-thermal lens spectrum of nitrobenzene in the 400–700 nm region measured using a white light thermal lens spectrophotometer. The measured spectrum coincides well with the absorbance spectrum in the red region above 600 nm. For shorter wavelength the photo-thermal spectrum falls below the values of the absorbance. We associate this difference to the presence of scattering effects that affect the value of the absorbance but not the value of the photo-thermal signal. Absorption as small as 10?3 cm?1 can be measured with 1–2 mW of optical power.