Structure transition of Au18 from pyramidal to a hollow-cage during soft-landing onto a TiO2(110) surface

Au18 is a unique gold cluster in that, in the gas phase, two distinct isomers, namely, golden hollow-cage and golden pyramid, can coexist (ACS Nano, 2009, 3, 1225). We perform a Born-Oppenheimer molecular dynamics (BOMD) simulation to confirm the structural stability of the two isomers at ambient temperature. Most importantly, we study the possible structure conversion between the two isomers when they are soft-landed onto a rutile TiO2(110) surface. Our BOMD simulation indicates that the Au18 cluster can undergo a transition from pyramidal to a hollow-cage structure during soft landing onto the rutile TiO2(110) surface at ambient temperature, suggesting the high selectivity of the hollow-cage structure over the pyramidal structure in realistic soft-landing experiments.