Table 1. Rate Coefficients for Neutral and Ionic Gas-Phase Reactions in the Sodium Model.

number	reaction	rate coefficienta
Neutral Chemistry
R1	Na + O3 → NaO + O2	1.1 × 10–9 exp(−116/T)
R2	NaO + O → Na + O2	(2.2 × 10–10)(T/200)1/2
R3	NaO + O3 → Na + 2O2	3.2 × 10–10 exp(−550/T)
R4	NaO + H2 → NaOH + H	1.1 × 10–9 exp(−1100/T)
R5	NaO + H2 → Na + H2O	1.1 × 10–9 exp(−1400/T)
R6	NaO + H2O → NaOH + OH	4.4 × 10–10 exp(−507/T)
R7	NaOH + H → Na + H2O	4 × 10–11 exp(−550/T)
R8	NaOH + CO2 (+M) → NaHCO3	(1.9 × 10–28)(T/200)−1
R9	NaHCO3 + H → Na + H2CO3	(1.84 × 10–13)T0.777 exp(−1014/T)
R10	Na + O2 (+M) → NaO2	(5.0 × 10–30)(T/200)−1.22
R11	NaO2 + O → NaO + O2	5.0 × 10–10 exp(−940/T)
R12	2NaHCO3 (+M) → dimer	(8.8 × 10–10)(T/200 K)−0.23
Ion–Molecule Chemistry
R20	Na + O2+ → Na+ + O2	2.7 × 10–9
R21	Na + NO+ → Na+ + NO	8.0 × 10–10
R22	Na+ + N2 (+M) → Na·N2+	(4.8 × 10–30)(T/200)−2.2
R23	Na+ + CO2 (+M) → Na·CO2+	(3.7 × 10–29)(T/200)−2.9
R24	Na·N2+ + X → Na.X+ + N2 (X = CO2, H2O)	6 × 10–10
R25	Na·N2+ + O → NaO+ + N2	4 × 10–10
R26	NaO+ + O → Na+ + O2	1 × 10–11
R27	Na·O+ + N2 → Na·N2+ + O	1 × 10–12
R28	Na·O+ + O2 → Na+ + O3	5 × 10–12
R29	Na·Y+ + e– → Na + Y (Y = N2, CO2, H2O, O)	(1 × 10–6)(T/200)−1/2
R30	Na+ + e– → Na + hν	(3.9 × 10–12)(T /200)−0.74
Photochemical Reactions
R31	NaO + hν → Na + O	5.5 × 10–2
R32	NaO2 + hν → Na + O2	1.9 × 10–2
R33	NaOH + hν → Na + OH	1.8 × 10–2
R34	NaHCO3 + hν → Na + HCO3	1.3 × 10–4
R34	Na + hν → Na+ + e–	2 × 10–5

^aUnits: unimolecular, s^–1; bimolecular, cm³ molecule^–1 s^–1; termolecular, cm⁶ molecule^–2 s^–1. Rate coefficients are from Plane²⁷² apart from that for reaction R30, which is calculated by Badnell.¹¹³