COUPLED-CLUSTER CALCULATIONS FOR LINEAR C-8(-)(X)OVER-TILDE(2)PI(G) AND (C)OVER-TILDE(2)PI(U)) AND C-8(X)OVER-TILDE (3)SIGMA(-)(G))

Large-scale open-shell coupled cluster calculations have been carried out for the two lowest (II)-I-2 states of C-8(-) and the electronic gr ound state of linear C-8. The calculated spectrum of the (IIu)-I-2 <-- ($) over tilde X (IIg)-I-2 transition is in good agreement with the r ecent neon matrix absorption spectrum of Freivogel, Fulara, Jacobi and Maier. The calculated adiabatic electron affinity of C-8 is 4.348 eV, in close agreement with the experimental value of 4.379 +/- 0.006 eV. The 4.66 eV photoelectron spectrum of C-8(-) is dominated by the adia batic peak; the 1(0)(1) and 3(0)(1) transitions have relative intensit ies of 24% and 13%, respectively.