Void defect induced magnetism and structure change of carbon material-2, Graphene molecules

TL;DR

This study investigates void-defect induced magnetism in graphene molecules, revealing stable triplet spin states and infrared spectra that match astronomical observations and laboratory experiments, suggesting cosmic relevance.

Contribution

It demonstrates that void defects induce magnetic triplet states in graphene molecules and links their infrared spectra to astronomical and laboratory data.

Findings

Void defects lead to stable triplet spin states in graphene molecules.

Infrared spectra of defected graphene molecules match astronomical observations.

Laboratory spectra of laser-induced carbon plasma resemble cosmic carbon signatures.

Abstract

Void-defect is a possible origin of ferromagnetic feature on pure carbon materials. In our previous paper, void-defect on graphene-nanoribbon show highly polarized spin configuration. In this paper, we studied cases for graphene molecules by quantum theory, by astronomical observation and by laboratory experiment. Model molecules for the density functional theory are graphene molecules of C23 and C53 induced by a void-defect. They have carbon pentagon ring within a hexagon network. Single void has three radical carbons, holding six spins. Those spins make several spin-states, which affects to molecular structure and molecular vibration, finally to infrared spectrum. The stable spin state was triplet, not singlet. This suggests magnetic pure carbon molecule. It was a surprise that those molecules show close infrared spectrum with astronomically observed one, especially observed on carbon rich planetary nebulae. We could assign major band at 18.9 micrometer, and sub-bands at 6.6, 7.0, 7.6, 8.1, 8.5, 9.0 and 17.4 micrometer. Also, calculated spectrum roughly coincides with that of laboratory experiment by the laser-induced carbon plasma, which is an analogy of cosmic carbon creation in interstellar space.