Significantly improved XeF(C→A) laser energy density and efficiency have been obtained using electron‐beam excited Ar‐Xe gas mixtures at pressures up to 10 atm which contain both NF3 and F2. Maximum blue‐green laser pulse energy density in excess of 1.0 J/liter was obtained, corresponding to an intrinsic electrical‐optical energy conversion efficiency estimated to be in the 0.5%–1.0% range. Comprehensive, time‐resolved absolute measurements of XeF(C→A) fluorescence, laser energy, and gain were carried out for a wide variety of experimental conditions. Analysis of these data has resulted in identification of the dominant transient absorbing species in the laser medium. For the laser mixtures investigated in this work, the primary blue/green absorption processes have been identified as photoionization of the 4p, 3d, and higher lying states of Ar, and of the Xe 6p and 5d states, and photodissociation of Ar2(3∑+u) and Ar+3.