Reactive high-power impulse magnetron sputtering discharge has been studied experimentally combining optical emission, absorption, and laser-based diagnostic techniques. The quantification of the atomic ground state densities is performed using optical emission spectroscopy. Hysteresis behavior as a function of molecular oxygen flow fraction in Ar-O2 mixture has been observed for numerous discharge parameters, such as the ground state density of O atoms, density of the sputtered atoms and ions, Ar metastables, etc. The obtained atomic number densities are found to be in full agreement with the known models of reactive sputter deposition. The relevant plasma kinetic mechanisms influencing the measured trends are analyzed. [ABSTRACT FROM AUTHOR]