Knowledge Bank

The vibrational dynamics of the first excited state of the acetylenic C-H stretch of cyclopropylacetylene (CPA) in both gas- and solution-phase are investigated. FTMW-detected infrared spectroscopy and high-resolution molecular-beam spectroscopy techniques are used to investigate the dynamics of ultracold molecular-beam CPA, while ultrafast time-domain transient absorption spectroscopy is used to study the dynamics of CPA in gas and dilute solution at room-temperature. The newly developed FTMW-detected IR spectrometer provides fast infrared frequency scanning rates (scanning speeds of up to $18cm-1/hr)$ as well as high sensitivity to detect weak infrared transitions. With the newly accessible information is achieved. Both FTMW-detected IR spectroscopy and femtosecond pump-probe spectroscopy show a very fast initial IVR rate of the first excited state of the acetylenic C-H stretch of CPA. When CPA is solvated ($0.05MCCl4$ solution), the IVR rate maintains the room-temperature isolated molecule value. The solvent contribution to the total relaxation rate in solution $(kTOT=KIVR+kVER)$ is minor and the main effects of the solvent are attributed to pure dephasing effects that destroy the intramolecular coherence.