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Kinetics of the reaction of CO3˙-(H2O)n, n = 0, 1, 2, with nitric acid, a key reaction in tropospheric negative ion chemistry.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Linde, Christian Van Der Tang, Wai K. Siu, Chi-Kit Beyer, Martin K. |
| Copyright Year | 2018 |
| Abstract | A significant fraction of nitrate in the troposphere is formed in the reactions of HNO3 with the carbonate radical anion CO3˙- and the mono- and dihydrated species CO3˙-(H2O)1,2. A reaction mechanism was proposed in earlier flow reactor studies, which is investigated here in more detail by quantum chemical calculations and experimental reactivity studies of mass selected ions under ultra-high vacuum conditions. Bare CO3˙- forms NO3-(OH˙) as well as NO3-, with a total rate coefficient of 1.0 × 10-10 cm3 s-1. CO3˙-(H2O) in addition affords stabilization of the NO3-(HCO3˙) collision complex, and thermalized CO3˙-(H2O) reacts with a total rate coefficient of 6.3 × 10-10 cm3 s-1. A second solvent molecule quenches the reaction, and only black-body radiation induced dissociation is observed for CO3˙-(H2O)2, with an upper limit of 6.0 × 10-11 cm3 s-1 for any potential bimolecular reaction channel. The rate coefficients obtained under ultra-high vacuum conditions are smaller than in the earlier flow reactor studies, due to the absence of stabilizing collisions, which also has a strong effect on the product branching ratio. Quantum chemical calculations corroborate the mechanism proposed by Möhler and Arnold. The reaction proceeds through a proton-transferred NO3-(HCO3˙) collision complex, which can rearrange to NO3-(OH˙)(CO2). The weakly bound CO2 easily evaporates, followed by evaporation of the more strongly attached OH˙, if sufficient energy is available. |
| Starting Page | 10838 |
| Ending Page | 10845 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/c7cp07773d |
| PubMed reference number | 29473922 |
| Journal | Medline |
| Volume Number | 20 |
| Issue Number | 16 |
| Alternate Webpage(s) | https://scholars.cityu.edu.hk/files/28663620/Kinetics_of_the_reaction_of_CO3_H2O_N_n_0_1_2_with_nitric_acid_a_key_reaction_in_tropospheric_negative_ion_chemistry.pdf |
| Alternate Webpage(s) | https://pubs.rsc.org/en/content/articlepdf/2018/cp/c7cp07773d |
| Alternate Webpage(s) | http://www.rsc.org/suppdata/c7/cp/c7cp07773d/c7cp07773d1.pdf |
| Alternate Webpage(s) | https://doi.org/10.1039/c7cp07773d |
| Journal | Physical chemistry chemical physics : PCCP |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |