Thermochemical properties from ab initio calculations: pi- and sigma-free radicals of importance in soot formation: (C3H3)-C-center dot (propargyl), (C4H3)-C-center dot, (C13H9)-C-center dot (phenalenyl), (C6H5)-C-center dot (phenyl), (C10H7)-C-center dot (naphthyl), (C14H9)-C-center dot (anthryl), (C14H9)-C-center dot (phenanthryl), (C16H9)-C-center dot (pyrenyl), (C12H7)-C-center dot (acenaphthyl), and (C12H9)-C-center dot (biphenylyl)