Electronic and infrared absorption spectra of linear and cyclic C6+ in a neon matrix

Electronic and infrared absorption spectra of mass-selected C-6(+), generated by dissociative electron impact ionization of C6Cl6 and C6Br6, have been recorded in 6 K neon matrices. Linear and cyclic forms of C-6(+) have been observed. The (2)Pi(g)<--X (2)Pi(u) electronic transition of linear C-6(+) has its origin band at 646 nm whereas for the (2) B-2(2)<--X (2)A(1) system of the cyclic isomer it lies at 570 nm. An infrared active fundamental mode in the ground electronic state of C-6(+) is observed at 2092 and 1972 cm-1 for the linear and cyclic isomer, respectively. (C) 2004 American Institute of Physics.