NEW F-VALUES IN CI AND THE CNO ABUNDANCES IN THE SUN

In an attempt to refine our knowledge of the solar abundances of the CNO elements, we discuss in this paper the implications of a new accurate set of oscillator strengths recently calculated in intermediate coupling for the 2p(2P(o))nl-2p(2P(o))n'l' E1 transitions of astrophysical interest in C I and also for the forbidden transitions within the 2p2 ground configuration. As with previous analyses devoted to nitrogen and oxygen, configuration interaction effects have been considered in the calculations in a detailed way and empirical adjustments have been introduced in the diagonal Hamiltonian matrix elements in order to improve the agreement between theoretical eigenvalues and experimental energy differences. The new LTE result, based on a sample of 55 E1 transitions observed in the visible and in the near infrared regions, is A(C) = 8.60 +/- 0.03 in the usual logarithmic scale. Taking departures from LTE into account leads, for a sample of 31 weak lines, to a mean result A(C) = 8.57 +/- 0.03 in agreement with recent determinations.