Methods. All DFT calculations described here have been performed with Gaussian program package using the PBE0 functional and G-31g(d) basis set. More details and examples can be found in references 9 through 11. This level of theory has been proven highly successful, treating all systems (large and small), at various levels and kinds of calculations in a uniform, unbiased and fairly accurate way. For example, all bandgaps ("bulk" and "surface") of the best known 5-, 7, and 9-AGNRs have been recently predicted with accuracy better or equal to 1%. Thus, the present computational scheme is adequate for the current work. The visualization of the results, as before was accomplished using the GaussView software.