Is 2-D Graphite an Ultimate Large Hydrocarbon? II. Structure and Energy Spectra of Polycyclic Aromatic Hydrocarbons with Defects

Abstract

The structure and energy spectra of four classes of polybenzenoid hydrocarbons with different edge structures, a large number N (N ∼ 10 4 ) of carbon atoms, and different types of defect states (Tamm, Schottky and chemisorption states) have been studied theoretically. Several types of (probably) stable monoradicals and triplet biradicals with singly occupied MOs in the energy gap (molecular analogues of semiconductors with defect states) are characterized which could be used in the molecular electronics. A new concept for viewing high-spin π systems with ferromagnetically coupled electrons within the half-filled band of NBMOs in term of point defects (vacancies) was developed. The NBMOs can be considered as surface states (Tamm or Schottky).

Schultz and Modified Schultz Polynomials of Coronene Polycyclic Aromatic Hydrocarbons

“…Polycyclic Aromatic Hydrocarbons and Circumcoronene Series of Benzenoid are two families of hydrocarbon molecules, such that their structure is consisting of Benzene C 6 H 6 or cycles with length six C 6 by defferent componds. In a series of papers, some properties and more historical details of hydrocarbon molecules are studed [44][45][46][47][48][49][50][51][52][53][54][55][56][57] and some applications of Benzenoid system are presented in many papers [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74].…”

Concealed Coronoid Hydrocarbons with Enhanced Antiaromatic Circuit Contributions as Models for Schottky Defects in Graphenes

“…Graphenes are well-defined, nanosized polycyclic aromatic hydrocarbons having potential uses in the fabrication organic electronic devices [10]. Removal of a single carbon atom from a graphite system generates a point defect that is a one-atom hole (called a Schottky defect) [11]. Using Aihara's topological superaromatic stabilization energy (t-SSE) index, it was shown that coronoid related systems that were HMO (Hückel MO) diradicals but VB (valence-bond) nonradicals (Kekuléan systems) displayed relatively more enhanced macrocyclic antiaromatic contributions (more negative t-SSE values) [2].…”

Structural and Electronic Properties of Low-Dimensional C-Nanoassemblies and Possible Analogues for Si (and Ge)

“…Cluster. Dietz et al [12] considered a variety of localized defect states (e.g., impurity defects) as well as topological defects, in two-dimensional graphite. Independently, Peeters et al [13] have reported results on a planar B 12 cluster embedded in graphenic fragments of different sizes.…”