H trapping at the metastable cation vacancy in <b>α</b>-Ga₂O₃ and <b>α</b>-Al₂O₃

Cation-anion vacancy complexes in semiconducting compounds

Hydrogen in tungsten: Absorption, diffusion, vacancy trapping, and decohesion

Understanding the interaction between atomic hydrogen and solid tungsten is important for the development of fusion reactors in which proposed tungsten walls would be bombarded with high energy particles including hydrogen isotopes. Here, we report results from periodic density-functional theory calculations for three crucial aspects of this interaction: surface-to-subsurface diffusion of H int...

Electrostatic trapping of metastable NH molecules

We report on the Stark deceleration and electrostatic trapping of NH (a ∆) radicals. In the trap, the molecules are excited on the spin-forbidden A Π ← a ∆ transition and detected via their subsequent fluorescence to the X Σ ground state. The 1/e trapping time is 1.4 ± 0.1 s, from which a lower limit of 2.7 s for the radiative lifetime of the a ∆, v = 0, J = 2 state is deduced. The spectral pro...

The cation-vacancy ordering transition in dehydrated Na 6 sodalite

Variable-temperature synchrotron x-ray powder diffraction data from dehydrated Na 6 ͓Al 6 Si 6 O 24 ] reveal a structural phase transition that involves both the commensurate ordering of the extra-framework Na cations and a one-dimensional incommensurate modulation of the framework. Peak splittings and superlattice reflections implicate an orthorhombically-distorted volume-doubled supercell at r...

Kinetic Trapping of Metastable Amino Acid Polymorphs

Second harmonic generation (SHG) microscopy measurements indicate that inkjet-printed racemic solutions of amino acids can produce nanocrystals trapped in metastable polymorph forms upon rapid solvent evaporation. Polymorphism impacts the composition, distribution, and physico-kinetic properties of organic solids, with energetic arguments favoring the most stable polymorph. In this study, unfav...