Lifetimes of the 3d2D and 4d2D terms of lithium are found to be 16.7±1.0 nsec and 42.3±1.5 nsec by counting single quanta with a delayed-coincidence method.
F. KARSTENSEN and J. SCEIRAMM, "Experimental Determination of Lifetimes for the 3 D and 4 D Terms of Lithium," J. Opt. Soc. Am. 57, 654-656 (1967)