Infrared diode laser spectroscopic investigation of four C–H stretching vibrational modes of propylene oxide

The high resolution ro-vibrational spectra of propylene oxide have been recorded for the first time in the C–H stretching region using a rapid scan infrared laser spectrometer equipped with an astigmatic multipass cell. Detailed analyses of the three C–H bands centered at 2942 and 2975 cm−1 reveal that there are significant perturbations in the methyl C–H symmetric and the two near-degenerate asymmetric fundamental bands. Low resolution Fourier transform infrared spectra of propylene oxide have also been measured with a static gas sample and under supersonic jet conditions. The MP2/6-311++G(d,p) harmonic and anharmonic frequency calculations have been performed to aid the C–H stretching band assignment.