Experimental lifetimes of some levels belonging to the3p5nd (n=4,5,6,7)configurations of Ar I

Lifetimes of twenty-three nonresonant levels belonging to the $3p^5\mathrm{nd} \mathrm{}(n=4,5,6,7\mathrm{})\mathrm{}$ configurations of Ar I have been measured. The single-photon delayed-coincidence method has been used to obtain the lifetime values given in the present work. As far as we know, no previous experimental results exist for sixteen of these levels. The experimental error was in the range from 1 to 10%. Our results have been compared with other experimental values and with our calculations performed in $\mathrm{jK}$ coupling and Coulomb approximation and with the intermediate-coupling results given in the literature.