Computational study on NiAl: ground state, structure, and spectroscopic constants using density- functional theory

The least computational expensive Hamiltonian (methods) and wavefunction (basis sets) for diatomic nickel-aluminum (NiAl), was calculated, along with the ground state, bond length, frequency, and binding energy. Researchers believe nickel-aluminum can be used in high performance turbine jet engines, in place of aluminum-coated nickel. The effects of basis functions under increasing levels of theory were compared to methods under increasing levels of theory. The free energy at two possible ground states, doublet or quartet, of nickel-aluminum was compared. The results consistently show the ground-state of nickel-aluminum is the doublet, and therefore has a bond between two valence electrons, one from each nickel and aluminum, and one unpaired electron. The data converged when using large number of basis sets, but did not produce precise results when compared with different methods. Results suggest the density-functional theory (DFT) and an augmented correlation consistent basis set are needed, at minimum, to properly optimize nickel-aluminum. The least computationally expensive, most precise basis set/method combination for diatomic NiAl allows for further research in the least computationally expensive combination, of method and basis set, for large microclusters of NiAl, which could be used in engines as well.