CAN LINEAR CARBON CHAINS BE SYNTHESIZED

Results of first-principles, density-functional calculations on two in teracting polyyne chains are presented. The results predict the existe nce of a stable configuration of two crosslinked chains. The energy ba rrier separating this configuration from that of the non-interacting c hains 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 a ccompanied by a change from semiconducting to metallic behaviours, in accordance with the experimentally observed changes in UV-VIS spectra and electronic conductivity.