Photo-induced production of sp-hybridized carbon species from Ag-coated polytetrafluoro ethylene (PTFE)

Carbon solids based on sp hybridization, although subject of intense experimental efforts, seem to be the most elusive of the different carbon families [1]. The existence of linear chains of carbon atoms linked by alternating single and triple bonds (polyyne) or double bonds (polycumulene) with stabilizing molecular complexes at the end of the chains, has been recognized in interstellar molecular clouds and can be artificially produced by different chemical routes [2]. Polyyne and polycumulene chains are very reactive: exposure to oxygen and/or water completely destroys these species [1], and at room temperature they spontaneously undergo chain–chain cross-linking reaction, evolving towards an sp2 phase [2]. Isolated carbon chains have been extensively studied only in the gas phase [3] or by means of matrix isolation spectroscopy at very low temperature [4].