The Hubbard model for alternant and nonalternant systems

摘要

In this paper we consider the effects of two‐electron, one‐center interactions when added to the one‐electron, two‐center molecular orbital model. There are, therefore, two parameters considered: The standard Hu¨ckel &bgr; (two‐center, one‐electron) term and the Hubbard one‐center, two‐electron termU. It is shown how the change in the ground state as one changes theU/&bgr; ratio is highly dependent on the presence or absence of odd member rings.