Chaos and dynamics on 0.5–300 ps time scales in vibrationally excited acetylene: Fourier transform of stimulated-emission pumping spectrum

A recently proposed technique based on the Fourier transform of the spectrum is applied to the stimulated-emission pumping spectrum of acetylene at ∼26 500 ${\mathrm{cm}}^{\mathrm{-}1}$ above the vibrational ground state. Correlations on two different time scales (∼3 and ∼45 ps) were found from analysis of low-resolution (0.3 ${\mathrm{cm}}^{\mathrm{-}1}$) and high-resolution (0.05 ${\mathrm{cm}}^{\mathrm{-}1}$) spectra, respectively. Additional structure produced dynamic information on a wider (0.5–300 ps) time scale. The results show that acetylene at 26 500 ${\mathrm{cm}}^{\mathrm{-}1}$ is in the transition from the regular to the chaotic regime.