Abstract—The method of molecular dynamics along with the flexible model of molecules are used to study the spectral characteristics of systems of clusters of (H2O)n, (O2)m(H2O)n, and (O)i(H2O)n, m≤2, i≤4,10≤n≤50. It is demonstrated that the integral intensity of absorption of IR radiation decays after water clusters adsorb oxygen. In addition, the adsorption of oxygen causes a significant decrease in the reflection coefficient R of monochromatic IR radiation. In so doing, the R(ω) spectrum splits into bands and exhibits seven peaks in the frequency region of 0≤ ω≤ 3500 cm–1. The dissociation of oxygen molecules captured by clusters makes the peaks of R(ω) spectrum more resolved. The attachment of molecular oxygen by clusters leads to decay of the power of their IR radiation, while the capture of atomic oxygen, on the contrary, is accompanied by an increase in the rate of dissipation of energy accumulated by water aggregates.