Functionalization of (n, 0) CNTs (n = 3–16) by uracil: DFT studies Mahmoud Mirzaei, Kun Harismah, Elham Jafari, Oğuz Gülseren and Ali Shokuhi Rad Eur. Phys. J. B, 91 1 (2018) 14 Published online: 17 January 2018 DOI: 10.1140/epjb/e2017-80404-1