Low Hydroxylated Fullerenes: Stability, Thermal Behavior, and Vibrational Properties

Extensive density functional theory (DFT) calculations dedicated to analyze the stability, thermal behavior, as well as the infrared (IR) and Raman spectra of low hydroxylated C60(OH)12 fullerenols are presented. Adsorbed configurations in which OH groups form various types of molecular islands on the carbon surface are the preferred atomic arrays, while random distributions of hydroxyl species are the highest energy molecular structures. It is found that the formation of local networks of hydrogen-bonded OH groups plays a fundamental role in the stability of these complexes. The calculated dipole moments, polarizability values, optical gap, and Fukui functions of C60(OH)12 isomers strongly depend on the structure of the hydroxyl overlayer, thus being an important parameter to tune the material properties. DFT Born–Oppenheimer molecular dynamics calculations at T = 300 K reveal that aggregated forms of OH groups on the fullerene surface show an interesting dynamical behavior, characterized by a continuous...