Surface Ionization Mass Spectrometric Studies of the Li/C₆₀ System

Abstract

We have studied the Li/C₆₀ system by the surface ionization mass spectrometry. We have investigated a possibility of the Li@C₆₀ formation via the collisions between Li⁺and C₆₀ ⁻ ions in a plasma state, which was predicted by an ab initio molecular dynamics simulation. The LiC₆₀ complex was unambiguously observed. Our results do not allow direct determination of the LiC₆₀ structure but indicate that Li is inside the C₆₀ cage. We have determined the ionization potential of Li@C₆₀ complex (IP = 5.9 ± 0.1 eV), which agrees well with the calculated value of the IP of Li@C₆₀.