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1. Branching Ratio for O + H ₃ ⁺ Forming OH ⁺ + H ₂ and H ₂ O ⁺ + H

   https://doi.org/10.3847/1538-4357/ac41ce  

   Hillenbrand, Pierre-Michel; Ruette, Nathalie de; Urbain, Xavier; Savin, Daniel W. (March 2022, The Astrophysical Journal)

   Abstract The gas-phase reaction of O + H 3 + has two exothermic product channels: OH + + H 2 and H 2 O + + H. In the present study, we analyze experimental data from a merged-beams measurement to derive thermal rate coefficients resolved by product channel for the temperature range from 10 to 1000 K. Published astrochemical models either ignore the second product channel or apply a temperature-independent branching ratio of 70% versus 30% for the formation of OH + + H 2 versus H 2 O + + H, respectively, which originates from a single experimental data point measured at 295 K. Our results are consistent with this data point, but show a branching ratio that varies with temperature reaching 58% versus 42% at 10 K. We provide recommended rate coefficients for the two product channels for two cases, one where the initial fine-structure population of the O( 3 P J ) reactant is in its J = 2 ground state and the other one where it is in thermal equilibrium. 

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2. Photoelectron Spectroscopy of the Aminomethoxide Anion, H ₂ C(NH ₂ )O ^–

   https://doi.org/10.1021/acs.jpca.8b02921  

   Oliveira, Allan M.; Lehman, Julia H.; Lineberger, W. Carl (May 2018, The Journal of Physical Chemistry A)
3. Emerging Nonvalence Anion States of [Isoprene-H·]·H ₂ O Accessed via Detachment of OH ^– ·Isoprene

   https://doi.org/10.1021/acs.jpca.0c01250  

   Dobulis, Marissa A.; Thompson, Michael C.; Patros, Kellyn M.; Sommerfeld, Thomas; Jarrold, Caroline Chick (March 2020, The Journal of Physical Chemistry A)
4. Plasma-droplet interaction study to assess transport limitations and the role of ^⋅ OH, O ^⋅ ,H ^⋅ ,O ₂ (a ¹ Δ _g ),O ₃ , He(2 ³ S) and Ar(1s ₅ ) in formate decomposition

   https://doi.org/10.1088/1361-6595/ac2676  

   Nayak, Gaurav; Oinuma, Gaku; Yue, Yuanfu; Santos Sousa, João; Bruggeman, Peter J (November 2021, Plasma Sources Science and Technology)

   Abstract Plasmas interacting with liquid microdroplets are gaining momentum due to their ability to significantly enhance the reactivity transfer from the gas phase plasma to the liquid. This is, for example, critically important for efficiently decomposing organic pollutants in water. In this contribution, the role of ⋅ OH as well as non- ⋅ OH-driven chemistry initiated by the activation of small water microdroplets in a controlled environment by diffuse RF glow discharge in He with different gas admixtures (Ar, O 2 and humidified He) at atmospheric pressure is quantified. The effect of short-lived radicals such as O ⋅ and H ⋅ atoms, singlet delta oxygen (O 2 ( a 1 Δ g )), O 3 and metastable atoms of He and Ar, besides ⋅ OH radicals, on the decomposition of formate dissolved in droplets was analyzed using detailed plasma diagnostics, droplet characterization and ex situ chemical analysis of the treated droplets. The formate decomposition increased with increasing droplet residence time in the plasma, with ∼70% decomposition occurring within ∼15 ms of the plasma treatment time. The formate oxidation in the droplets is shown to be limited by the gas phase ⋅ OH flux at lower H 2 O concentrations with a significant enhancement in the formate decomposition at the lowest water concentration, attributed to e − /ion-induced reactions. However, the oxidation is diffusion limited in the liquid phase at higher gaseous ⋅ OH concentrations. The formate decomposition in He/O 2 plasma was similar, although with an order of magnitude higher O ⋅ radical density than the ⋅ OH density in the corresponding He/H 2 O plasma. Using a one-dimensional reaction–diffusion model, we showed that O 2 ( a 1 Δ g ) and O 3 did not play a significant role and the decomposition was due to O ⋅ , and possibly ⋅ OH generated in the vapor containing droplet-plasma boundary layer. 

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5. Editors’ Choice—Vibrational Properties of Oxygen-Hydrogen Centers in H ⁺ - and D ⁺ -Implanted Ga ₂ O ₃

   https://doi.org/10.1149/2162-8777/abd458  

   Portoff, Amanda; Venzie, Andrew; Qin, Ying; Stavola, Michael; Fowler, W. Beall; Pearton, Stephen J. (December 2020, ECS Journal of Solid State Science and Technology)

   The ion implantation of H⁺and D⁺into Ga₂O₃produces several O–H and O–D centers that have been investigated by vibrational spectroscopy. These defects include the dominant V_Ga(1)-2H and V_Ga(1)-2D centers studied previously along with additional defects that can be converted into this structure by thermal annealing. The polarization dependence of the spectra has also been analyzed to determine the directions of the transition moments of the defects and to provide information about defect structure. Our experimental results show that the implantation of H⁺(or D⁺) into Ga₂O₃produces two classes of defects with different polarization properties. Theory finds that these O–H (or O–D) centers are based on two shifted configurations of a Ga(1) vacancy that trap H (or D) atom(s). The interaction of V_Ga(1)-nD centers with other defects in the implanted samples has also been investigated to help explain the number of O–D lines seen and their reactions upon annealing. Hydrogenated divacancy V_Ga(1)-V_Ocenters have been considered as an example. 

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