THE ABSORPTION-SPECTRUM OF CARBON-MONOXIDE IN THE CO(3-PI-R,A) STATE BETWEEN 215-NM AND 285-NM

By e-beam excitation of a He/CO mixture the CO (3-PI-r, a) state was sufficiently populated to allow the measurement of the absorption spectrum. The (0, 0), (1,1), (2,2) and (0,1) bands of the c3-PI <-- a 3-PI system of CO have been observed and the molecular constants T(e) = 92036.0 cm-1 (for the band head), omega-e = 2249.5 cm-1, omega-e x(e) = 29.5 cm-1 have been derived for CO(c). A new electronic state with T(e) = 91854.3 cm-1, omega-e = 848.4 cm-1, omega-e x(e) = 9.8 cm-1, B(e) = 1.351 cm-1, and alpha-e = 0.021 cm-1 was identified to be a 3-SIGMA state. It seems to be very likely that this state is the CO (3 p-sigma, 3-SIGMA, j) state discussed in the literature. The results indicate a perturbation of the upsilon = 1 levels of the new state by the CO (c, upsilon = 0) levels. Another strong perturbation is found in the upsilon = 4 levels. The three CO(3-SIGMA, b, upsilon' = 0, 1, 2) <-- CO (a, upsilon" = 0) bands were also investigated yielding for CO (b): T(e) = 83778 cm-1, omega-e = 2335 cm-1, omega-e x(e) = 59 cm-1 and B(e) = 1.86 cm-1.