Intermolecular self-interaction energies of magic clusters MAu4 (M=Ti and Zr)

Abstract

Two TiAu4 (or ZrAu4) clusters are known to bind to each other with unusually high (∼5–7eV) interaction energies at the Møller–Plesset second-order perturbation theory (MP2) level [T. K. Ghanty et al., J. Chem. Phys.120, 11363 (2004)]. Our MP2 calculations also show very high interaction energies of about 8eV for (TiAu4)2 and (ZrAu4)2. However, the strong MP2 bindings are found to be partly ascribable to large basis set superposition error (BSSE). The BSSE-corrected interaction energies are 4.63 and 4.25eV for (TiAu4)2 and (ZrAu4)2, respectively. We also found that there are Hartree–Fock wave function instabilities for the systems, implying that the restricted MP2 descriptions are potentially inadequate. High-level calculations are needed to draw clear conclusions.