On the identification of the vibrational spectrum of cyclic C-8 in solid Ar

A recent proposal to assign or reassign absorptions in Fourier transform in frared spectra of the products of evaporating graphite trapped in argon mat rices to linear C-13 and cyclic C-8 has been examined. An analysis of the e xperimental and theoretical data presented indicates that the claimed ident ification of linear C-13 is unwarranted. Simulations of spectra based on de nsity functional theory calculations and isotopic shift data indicate that an absorption at 1818.0 cm(-1) belongs to a carbon chain, and do not suppor t a revision of our earlier identification of the nu(12)(e(u)) fundamental of cyclic C-8 at 1844.2 cm(-1). (C) 2000 American Institute of Physics. [S0 021-9606(00)01603-2].