Quantum-Chemical Modeling of the Mass-analyzed Threshold Ionization Spectra of Ferrocene and Cobaltocene

The vibronic structures of the mass-selective threshold ionization spectra of ferrocene and cobaltocene are simulated within the framework of the density functional theory. Using (C5H5)2Co as an example, it is shown that the proposed levels of theory reproduce well the peak positions and relative intensities in the experimental high-resolution spectrum. This makes it possible to predict accurately changes in the molecular structure and vibrational frequencies on the ionization of metallocenes in the gas phase.