ELECTRONIC-SPECTRA OF LINEAR CARBON ANIONS

Resonance enhanced two colour photodetachment spectroscopy has been em ployed to probe several electronic transitions of mass selected anioni c carbon chains in the gas phase. Spectra of the A(2) Pi(g) <-- X-2 Pi (u) transition of C-5(-), A(2) Pi(u) <-- X-2 Pi(g) and B-2 Pi(u) <-- X -2 Pi(g) of C-7(-) and A(2) Pi(g) <-- X-2 Pi(u), B-2 Pi(g) <-- X-2 Pi( u) and C-2 Pi(g) <-- X-2 Pi(u) of C-9(-) were obtained, yielding origi n bands significantly narrower than those reported previously. In addi tion, two (x) (2) Pi(u) <-- X-2 Pi(g) (x=2,3) electronic transitions o f C-4(-) with band origins at 25989 and 28717 cm(-1) have been detecte d. The improvements in the resolution and extended scan range of the s pectra have enabled values for the gas to neon matrix shift for the vi bronic bands to be inferred. (C) 1998 Elsevier Science B.V.