Projects per year
The major obstacle that prevents reliable electronic structure studies of nanoparticles is the rapid increasing computational cost for benchmark calculations using coupled-cluster methods. We show that a CCSD(T) scheme with an MP2/CBS correction can reproduce accurate cohesive energies for magnesium clusters, and this scheme is much less computationally demanding than other reliable methods, so it is applied to Mgn with n up to 19, which enters the realm of nanoparticles. (The diameters of all Mg clusters n = 11 are >1 nm). With the extended benchmark data, we validate exchange-correlation functionals into the nanoparticle regime and use the two bestvalidated functionals to calculate the enthalpy of formation of Mg28, with a diameter of 1.30 nm. We also calculated the enthalpy of formation of all Mg clusters and nanoparticles from Mg2 to Mg19. This kind of reliable thermodynamic data on size-selected metal nanoparticles has been hard to come by, either experimentally or theoretically, but it is badly needed to support applications in catalysis, electrochemistry, and other technologies.