Knowledge Bank

Time dependent intramolecular vibrational relaxation (IVR) in the excited electronic state $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}B2$ of alkylanlitne molecules was directly monitored by employing a two-photon ionization process. Photoelectrons were produced by pump-probe picosecond laser pulses impinging on a jet-cooled molecular beam. The kinetic energies of photoelectrons were measured by a time of flight method. With the picosecond pump laser tuned to different vibrational modes in the excited electronic state of alkylaniline molecules and the probe laser adjusted to the different delay times, photoelectron spectra were recorded. The extended chain conformation ip-n-(trans)-alkylaniline and the coiled chain conformation [p-n-(gauche)-alkylaniline] exhibit remarkably different IVR behavior. The effect of the chain length on IVR will be also discussed.