High Resolution Lifetime Studies of the d³Πg, C¹Πgand D¹Σu⁺States in C₂with Applications to Estimates of the Solar Carbon Abundance

Lifetimes have been measured for a number of vibrational levels of the d 3 Π g , C 1 Π g and D 1 Σ u + states in the C 2 molecule using the High Frequency Deflection technique. Particular attention was paid to various rotational levels of the v ' = 6 level of the d 3 Π 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.