Isomerization and intermolecular solute-solvent interactions of ethyl isocyanate: Ultrafast infrared vibrational echoes and linear vibrational spectroscopy

The dynamics of ethyl isocyanate (EIC) in the solvent, 2-methylpentane (2MP), are investigated by examining the temperature dependences of the isocyanate (N=C=O) antisymmetric stretching mode's absorption spectrum and ultrafast infrared vibrational echo decay. By combining the spectral data and the vibrational echo data, an interesting picture of the EIC dynamics emerges. As such, electronic structure calculations of the isolated molecule show that trans and gauche forms should be stable, while the cis conformation is a saddle point on the potential surface.