High resolution lifetime studies of the d3PIsub(g), C1PIsub(g) and D1Σ+sub(u) states in C2 with applications to estimates of the solar carbon abundance

Lifetimes have been measured for a number of vibrational levels of the d3PIsub(g), C1PIsub(g) and D1Σ+sub(u) states in the C2 molecule using the High Frequency Deflection technique. Particular attention was paid to various rotational levels of the γ'=6 level of the d3PIsub(g) state but no decrease in lifetime was found indicating the absence of earlier suggested predissociation effects, which would be an explanation of the occurrence of the high-pressure carbon bands. For the d-a (Swan) bands oscillator strengths are found which are considerably higher than earlier estimates demanding a 40% decrease in the estimate of the solar carbon abundance. (Auth.)