Bimolecular processes in a low-density oxygen discharge

When excited by a microwave discharge, pairs of gaseous oxygen molecules radiate strong luminescence and display bimolecular oscillatory transitions. At low pressures the intensities of both processes have an unusual density dependence, increasing with decreasing density, indicating molecular competition between radiative and nonradiative decay schemes. The data provide the first direct observation of a weakly bound O2-O2 structure. © 1984 The American Physical Society.