Knowledge Bank

Experiments designed to simplify methane’s overtone spectrum as observed with a photoacoustic spectrometer have been performed. A Schwartz Ti:Sapphire laser operating in the ring configuration (approximate linewidth $0.001cm-1$) was tuned via an intracavity scanning etalon and galvoplate assembly. Positioned within the laser cavity was a newly designed cryostatically cooled photoacoustic cell. This cell was capable of cooling the methane sample to liquid nitrogen temperatures with no window warming effects. High resolution low temperature photoacoustic spectra were recorded within a small region of the $v1+3v3$ methane overtone centered at 11629 $cm-1$. Near doppler limited linewidth ($0.022cm-1$) and reduced rotational spectral congestion were observed.