NON-CLOSED-SHELL LINEAR CHAIN - H4N SYSTEM

The low-lying energy levels of a non-closed-shell linear chain consisting of 4n hydrogen atoms, each occupying a vertex of a regular polygon of 4n sides and contributing a single 1s electron, are studied with electron correlation taken into consideration in an approximate way within the framework of Löwdin's extension of the Hartree-Fock method. The nature of the wave functions and energy expressions for such a system with both orbital and spin degeneracies is discussed. It is shown that in the n=3 case the energy levels have the correct asymptotic behavior as the interatomic separation R assumes large values, and that a change of lattice spacing in the limit of small R could lead to a magnetic transition. © 1968 The American Physical Society.