RAIR spectra of H₂CO + H + O₂ (a; exp. 1), the H₂CO + H + O₂MLR spectrum (b), and its components multiplied by the coefficients derived from the MLR analysis: H₂CO + O₂ + H₂O (c; exp. 7; 1.2 coefficient), HCOOH (d; exp. 6; 0.3 coefficient), H₂O (e; exp. 8; 0.7 coefficient), and H + O₂ (f; exp. 9; 9.7 coefficient). Spectra are recorded after deposition at 10 K and are offset for clarity.