CAN LINEAR CARBON CHAINS BE SYNTHESIZED

Results of first-principles, density-functional calculations on two interacting polyyne chains are presented. The results predict the existence of a stable configuration of two crosslinked chains. The energy barrier separating this configuration from that of the non-interacting chains is large (about 1 eV per C atom). This is in agreement with the experimental observation that the properties of natural or synthesized polyyne change on a relatively long time scale. The crosslinking is accompanied by a change from semiconducting to metallic behaviours, in accordance with the experimentally observed changes in UV-VIS spectra and electronic conductivity.