Friends,
I have recently examined the effects of basis sets on Mulliken populations and other information in graphene and hexagonal BN layers. When I keep the verbosity level at 10 in the NanoLanguage Scripter then watch the SCF convergence process, I notice that the Mulliken populations are distributed among orbitals of various angular momentum. Parts of the population are allocated to s-orbitals, p-orbitals, and in the polarized basis sets, d-orbitals. In the bilayers of graphene and h-BN, I observe that there are minor changes in some orbital contributions to the Mulliken population when the interface is formed, while other orbital shells do not change at all.
How is this done, and is there any references related to decomposition of Mulliken populations into individual orbital factors? This has never been extensively described in the literature, and I had considered looking at orbital contributions to try identify the major orbitals responsible for the interface that forms between the two different monolayers via pi-pi orbital overlap and hence the cause of energy perturbations that open the band gap in the graphene layer.
