Ab initio study of the structure of oriented films of linearly chain carbon

Ab initio study of oriented carbon films consisting of bent carbon chains closely packed into a hexagonal cell has been reported. A new structural model of films has been presented. It has been shown that hydrogen impurity is necessary for the stabilization of their structure. Interatomic distances in the film both between chains and along them, as well as the bending angle of carbon chains, have been determined. It has been shown that carbon atoms in the chains have a polyene bond. The distances between chains ($5.0$ Å) theoretically determined in this work are in excellent agreement with the previously reported experimental data. The analysis of the electronic density of states shows that these films have the dielectric properties with a band gap of about $0.43$ eV. The distribution of the charge density along the chains in the film has been studied, which makes it possible to propose a model of the structural instability of such films.