Stabilities of isomers of LaC12+ and LaC13+

Theoretical studies that employ ab initio density functional techniques have been presented for the relative stabilities of isomers of LaC12+ and LaC13+. While LaC12+ exhibits the most stable isomer with La inserted into the carbon ring, LaC13+ exhibits the most stable structure in which the La atom is inside the ring. Our computations are consistent with the recent experimental study on LaCn+ isomers which suggests alternation of fast and slow ring isomers as a function of n.