Geometric structures and adsorption energies of mixed methanol and C60 cationic clusters produced within helium nanodroplets

Mass spectrometry is a useful technique for studying molecular cluster sizes, their distributions, compositions, and stability. Methanol and fullerenes are among the species identified in the interstellar medium and, due to their high abundance, their interactions are an interesting investigation topic. A mass spectrometric study of mixed clusters of methanol and C60 inside helium nanodroplets is presented. Anomalies in the distribution intensities or magic numbers were observed for [CH3OH]4[C60]m+,1 <= m <= 7. Water molecules within clusters were also detected, arising as one of the products of intermolecular methanol dehydration. Optimized and supposedly stable geometrical structures of these molecules are presented along with corresponding HOMO-LUMO gaps and adsorption energies. A linear decrease in adsorption energy and saturation at a critical cluster size was noticed.