More Like this

1. H trapping at the metastable cation vacancy in α -Ga ₂ O ₃ and α -Al ₂ O ₃

   https://doi.org/10.1063/5.0094707  

   Venzie, Andrew; Portoff, Amanda; Stavola, Michael; Fowler, W. Beall; Kim, Jihyun; Jeon, Dae-Woo; Park, Ji-Hyeon; Pearton, Stephen J. (May 2022, Applied Physics Letters)

   α-Ga₂O₃has the corundum structure analogous to that of α-Al₂O₃. The bandgap energy of α-Ga₂O₃is 5.3 eV and is greater than that of β-Ga₂O₃, making the α-phase attractive for devices that benefit from its wider bandgap. The O–H and O–D centers produced by the implantation of H⁺and D⁺into α-Ga₂O₃have been studied by infrared spectroscopy and complementary theory. An O–H line at 3269 cm⁻¹is assigned to H complexed with a Ga vacancy (V_Ga), similar to the case of H trapped by an Al vacancy (V_Al) in α-Al₂O₃. The isolated V_Gaand V_Aldefects in α-Ga₂O₃and α-Al₂O₃are found by theory to have a “shifted” vacancy-interstitial-vacancy equilibrium configuration, similar to V_Gain β-Ga₂O₃, which also has shifted structures. However, the addition of H causes the complex with H trapped at an unshifted vacancy to have the lowest energy in both α-Ga₂O₃and α-Al₂O₃. 

   more » « less
2. The non-covalently bound SO⋯H ₂ O system, including an interpretation of the differences between SO⋯H ₂ O and O ₂ ⋯H ₂ O

   https://doi.org/10.1039/C8CP05749D  

   Misiewicz, Jonathon P.; Noonan, Julia A.; Turney, Justin M.; Schaefer, Henry F. (November 2018, Physical Chemistry Chemical Physics)

   Despite the interest in sulfur monoxide (SO) among astrochemists, spectroscopists, inorganic chemists, and organic chemists, its interaction with water remains largely unexplored. We report the first high level theoretical geometries for the two minimum energy complexes formed by sulfur monoxide and water, and we report energies using basis sets as large as aug-cc-pV(Q+d)Z and correlation effects through perturbative quadruple excitations. One structure of SO⋯H 2 O is hydrogen bonded and the other chalcogen bonded. The hydrogen bonded complex has an electronic energy of −2.71 kcal mol −1 and a zero kelvin enthalpy of −1.67 kcal mol −1 , while the chalcogen bonded complex has an electronic energy of −2.64 kcal mol −1 and a zero kelvin enthalpy of −2.00 kcal mol −1 . We also report the transition state between the two structures, which lies below the SO⋯H 2 O dissociation limit, with an electronic energy of −1.26 kcal mol −1 and an enthalpy of −0.81 kcal mol −1 . These features are much sharper than for the isovalent complex of O 2 and H 2 O, which only possesses one weakly bound minimum, so we further analyze the structures with open-shell SAPT0. We find that the interactions between O 2 and H 2 O are uniformly weak, but the SO⋯H 2 O complex surface is governed by the superior polarity and polarizability of SO, as well as the diffuse electron density provided by sulfur's extra valence shell. 

   more » « less
3. Crystal Structure of Symmetric Ice X in H ₂ O–H ₂ and H ₂ O–He under Pressure

   https://doi.org/10.1021/acs.jpclett.1c00606  

   Lei, Jialin; Lim, Jinhyuk; Kim, Minseob; Yoo, Choong-Shik (May 2021, The Journal of Physical Chemistry Letters)
4. H ₂ evolution from H ₂ O via O–H oxidative addition across a 9,10-diboraanthracene

   https://doi.org/10.1039/D0CC05261B  

   Taylor, Jordan W.; Harman, W. Hill (November 2020, Chemical Communications)

   null (Ed.)

   The water reactivity of the boroauride complex ([Au(B 2 P 2 )][K(18-c-6)]; (B 2 P 2 , 9,10-bis(2-(diisopropylphosphino)-phenyl)-9,10-dihydroboranthrene) and its corresponding two-electron oxidized complex, Au(B 2 P 2 )Cl, are presented. Au(B 2 P 2 )Cl is tolerant to H 2 O and forms the hydroxide complex Au(B 2 P 2 )OH in the presence of H 2 O and triethylamine. [Au(B 2 P 2 )]Cl and [Au(B 2 P 2 )]OH are poor Lewis acids as judged by the Gutmann–Becket method, with [Au(B 2 P 2 )]OH displaying facile hydroxide exchange between B atoms of the DBA ring as evidenced by variable temperature NMR spectroscopy. The reduced boroauride complex [Au(B 2 P 2 )] − reacts with 1 equivalent of H 2 O to produce a hydride/hydroxide product, [Au(B 2 P 2 )(H)(OH)] − , that rapidly evolves H 2 upon further H 2 O reaction to yield the dihydroxide compound, [Au(B 2 P 2 )(OH) 2 ] − . [Au(B 2 P 2 )]Cl can be regenerated from [Au(B 2 P 2 )(OH) 2 ] − via HCl·Et 2 O, providing a synthetic cycle for H 2 evolution from H 2 O enabled by O–H oxidative addition at a diboraanthracene unit. 

   more » « less
5. 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. 

   more » « less