Ratio of the nuclear energy released in a Chapman-Jouguet detonation, q_CJ, to the increase in specific internal energy of the fuel needed to achieve the shocked state, Δ(e), as a function of fuel density. Open squares belong to a fuel composition of X(¹²C) = X(¹⁶O) = 0.5, while solid squares are for initial composition X(¹²C) = 0.2 and X(¹⁶O) = 0.8. A dotted line indicates the minimum q_CJ necessary for self-sustained detonation propagation q_CJ = Δ(e).