Calculated O(¹S) (top panel) and O(¹D) (bottom panel) production rate profiles, for different photon and electron impact dissociative excitation reactions of major cometary volatiles in C/2016 R2 when it was at 2.8 au from the Sun. The total gas production rate of CO is taken as 1.1 × 10²⁹ s⁻¹ with 0.3% H₂O, 18% CO₂, and 1% O₂ with respect to carbon monoxide. Here, hν represents a solar photon and e_ph is a suprathermal electron.