From K[ZnBP2O8] to K[(Zn0.5Al0.5)2P2O8]: Substitution-Induced Microporous Zincoaluminophosphate with a Congruent-Melting Behavior.

An open-frame aluminophosphate, K[(Zn0.5Al0.5)2P2O8] (KZAPO), was rationally designed by a substitution design strategy and synthesized by a high-temperature molten salt method. Compared with the parent crystal of K[ZnBP2O8], KZAPO was characterized by similar 4 × 8 × 8 networks, a comparable short-wave ultraviolet transparency and a more regular tetrahedral frame with the mixing of (ZnO4)6- and (AlO4)5- anionic groups, highlighting the multifunctional roles that anionic group mixing played in structural and property modulations. In particular, KZAPO was characterized by a high thermal stability (over 850 °C) and a congruent-melting behavior, being conducive to practical applications.

Change of coral carbon isotopic response to anthropogenic Suess effect since around 2000s.

The stable carbon isotope composition (δ13C) in coral skeletons can be used to reconstruct the evolution of the dissolved inorganic carbon (DIC) in surface seawater, and its long-term declining trend during the past 200 years (~1800-2000) reflects the effect of anthropogenic Suess effect on carbonate chemistry in surface oceans. The global atmospheric CO2 concentration still has been increasing since 2000, and the Suess effect is intensifying. Considering the coral's ability of resilience and acclimatization to external environmental stressors, the response of coral δ13C to Suess effect may change and needs to be re-evaluated. In this study, ten long coral δ13C time series synthesized from different oceans were used to re-evaluate the response of coral carbonate chemistry to Suess effect under the changing environments. These δ13C time series showed a long-term declining trend since 1960s, but the declining rates slowed in eight time series since around 2000s. Considering that the declining rates of the DIC-δ13C in surface seawater from the Hawaii Ocean Time-series Station and Bermuda Atlantic Time-series Station has not changed since 2000 compared with those during 1960-1999, the change in the coral δ13C trends at eight of ten locations may indicate that the response of coral δ13C to the anthropogenic Suess effect has changed since around 2000s. This change may have resulted from coral acclimatization to external environmental stressors. To adapt to acidifying oceans, coral may have the ability to regulate the source of DIC in extracellular calcifying fluid and/or the utilization way of DIC, therefore the response of coral δ13C to anthropogenic Suess effect will change accordingly.

Hybrid density functional studies of native defects and H impurities in wurtzite CdSe.

In this study, the formation energies and electronic properties of six native defects as well as H impurities in wurtzite (wz) CdSe are systematically investigated using hybrid density functional calculations. It is shown that native defects, including antisite CdSe and interstitial Cdi, may be sources of the unintentional n-type conductivity in CdSe under Se-poor conditions; meanwhile, the vacancy defect VSe is not a good donor. However, when the common H impurity is considered, it is suggested that both the substitutional impurity HSe and the interstitial impurity Hi are the dominant and effective origins of the unintentional n-type conductivity in Se-poor conditions. However, unintentional p-type conductivity in CdSe is challenging to form regardless of the growth conditions. Moreover, hybrid functional calculations of the electronic structures show that the six native point defects and the extrinsic impurities Hi and HSe will cause more or fewer changes in the band gap. Among all considered defects and impurities, it is found that only the interstitial defect Cdi introduces impurity levels into the band gap. In particular, the present hybrid functional calculations theoretically affirm that the vacancy defect VCd in CdSe can induce a 2 µB magnetic moment; however, other native defects will not introduce any magnetic moment.

Cold atom-atom-anion three-body recombination of 4He4HexLi- (x = 6 or 7) systems.

Atom-atom-anion three-body recombination (TBR) in mixed 4He and xLi- (x = 6 or 7) is investigated in the adiabatic hyperspherical representation by quantum mechanically solving the Schrödinger equation. The distributions of product states following these TBR processes are found to be relatively different for the two systems when the collision energy is less than roughly 0.6 mK × kB or 0.3 mK × kB for 4He4He6Li- and 4He4He7Li- systems, respectively, with kB being the Boltzmann constant. For 4He4He6Li- systems, the rate of recombination into (v=0) l = 04He6Li- molecular anions is the largest with v and l denoting the rovibrational quantum numbers, while the TBR rate that leads to the formation of l = 14He6Li- molecular anions is a little smaller than that of neutral 4He2 molecules. For 4He4He7Li- systems, neutral 4He2 molecules tend to be the most products, following the yields of l = 0 and 1 4He7Li- molecular anions. However, in spite of these distinctly different distributions, the products of molecular anions, the sum of l = 0 and 1 4HexLi- products, are relatively larger than that of neutral 4He2 molecules for both the two systems.