Vibrational dynamics of iron pentacarbonyl in cryogenic matrices.

Iron pentacarbonyl is a textbook example of fluxionality. We trap the molecule in cryogenic matrices to study the vibrational dynamics of CO stretching modes involved in the fluxional rearrangement. The infrared spectrum in Ar and N is composed of about ten narrow bands in the spectral range of interest, indicating the population of various lattice sites and a lowering of the molecular symmetry in the trapping sites.

Vibrational spectroscopy and dynamics of W(CO) in solid methane as a probe of lattice properties.

Methane solids present more than one accessible crystalline phase at low temperature at zero pressure. We trap W(CO) in CH and CD matrices between 8 and 35 K to probe the interaction between an impurity and its surrounding molecular solid under various physical conditions. Linear and nonlinear vibrational spectroscopies of W(CO) highlight different kinds of interaction and reveal new and remarkable signatures of the phase transition of methane.