Step-scan Fourier transform infrared absorption spectroscopy of liquid benzene cluster in a pulsed supersonic jet

We have obtained the infrared absorption spectrum of the jet-cooled C6H6 in the 800–5000 cm−1 region using step-scan Fourier transform infrared spectrometer combined with a pulsed supersonic jet system. The experimental spectrum was in good agreement with the convolution spectrum of the monomer band with the rotational temperature of ∼37 K and the broadbands of liquid C6H6, indicating the first spectroscopic evidence for the formation of supercooled liquid C6H6 cluster in the supersonic jet.