CARS THERMOMETRY IN A TRANSVERSELY HEATED GRAPHITE-TUBE ATOMIZER USEDIN ATOMIC-ABSORPTION SPECTROMETRY

An experimental setup for gas-temperature diagnostics using Coherent A nti-Stokes Raman Scattering (CARS) in very small sample volumes with g reat spatial and temporal temperature variations is presented. Studies have been started of a newly designed transversely heated graphite-tu be atomizer for atomic absorption spectrometry (Perkin-Elmer, 4100 ZL) . For the investigations, high spatial resolution and precise time syn chronization of the measurements and also automatic control of the tim e-dependent intensity of the anti-Stokes signal were realized. The gra phite-tube atomizer also offers the possibility of high-temperature-ga s spectroscopy. A high-temperature CARS spectrum of CO2, recorded in t he graphite tube at 2300 K, is shown for the first time. A number of h ot-band transitions in the spectral region of the Fermi doublet at a R aman shift from 1230 to 1450 cm(-1) was observed and assigned, making possible the use of CO2 as ''spectroscopic thermometer gas'', similar to N-2.