Journal of Physical Chemistry A, Vol.108, No.19, 4219-4223, 2004
Electronic absorption spectra of CnCl radicals (n=5, 6) and their cations in neon matrices
Electronic absorption spectra of C6Cl, C6Cl+, C5Cl, and C5Cl+ have been recorded in 6 K neon matrices. The bands observed are assigned to the B (2)Pi <-- X (2)Pi electronic transition of C6Cl, (3)Sigma(-) <-- X (3)Sigma(-) of C6Cl+, and (1)Sigma(+) <-- X (1)Sigma(+) of C5Cl+ with band origins at 545.8, 527.4, and 226.1 nm, respectively. Two electronic band systems are apparent for C5Cl and these are tentatively assigned to a (2)Pi <-- X (2)Pi transition with a band origin at 247.1 nm and to Sigma(+) <-- X (2)Pi at 532.3 nm. For each of the four molecules, several transitions due to the excitation of vibrational modes in the excited electronic states are observed. The spectral assignments in each case are based upon the observation of clear, vibronic progressions with appropriate spacing for C-C and C-Cl stretching modes and by comparison with the absorption spectra of the isoelectronic sulfur-terminated carbon chains.