Department of Physics, Banaras Hindu University, Varanasi-221 005, India E-mail : snthakur@satyam.net.in Manuscript received 20 September 2002 CO2 laser excited photoacoustic (PA) spectra of methanol, ethanol and trichloroethylene in the vapour phase have been recorded in the 9.6 µm and 10.6 µm spectral regions. A comparison with conventional IR and Raman spectra of these compounds shows that peaks in the PA spectra correspond to rotational contours of the vibrational bands with a limit of resolution better than 0.04 ,µm. The photoacoustic spectral peaks can be used in qualitative as well as quantitative spectrochemical analysis of air samples and can detect trace amounts (a few parts in 106) of these chemicals in air