Vibrational fine structures in photoelectron spectra of carbon ring clusters

Based on first-principles calculations, we study the vibrational fine structures of photoelectron spectroscopy used as a tool to identify carbon clusters. The hybrid density functional theory is used to perform electronic-structure calculations, then the fine structure is obtained based on the generalized harmonic oscillator model including displacement, frequency change, and mode mixing between the initial and final charge states. Calculational results for carbon-ring anion clusters enable clear identification of spectra observed in the past.