Structure and Hydrogen Bonding in CaSiD 1+ x : Issues About Covalent Bonding
We report here our high-resolution neutron powder diffraction and neutron vibrational spectroscopy study of ${\mathrm{CaSiD}}_{1+x}$ along with first-principles calculations, which reveal the deuterium structural arrangements and bonding in this novel alloy hydride. Both the structural and spectroscopic results show that, for $xg0$, D atoms start occupying a ${\mathrm{Ca}}_{3}\mathrm{Si}$ interstitial site. The corresponding $\mathrm{Si}\text{\ensuremath{-}}\mathrm{D}$ bond length is determined to be $1.82\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, fully $0.24\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ larger than predicted by theory. Thus, our neutron measurements are at odds with the strongly covalent $\mathrm{Si}\text{\ensuremath{-}}\mathrm{H}$ bonding in ${\mathrm{CaSiH}}_{1+x}$ that such calculations suggest, a result which may have implications for a number of ongoing studies of metal-hydrogen systems destabilized by Si alloying.
Introduction to the Theory of Thermal Neutron Scattering: Neutron optics
1. Introduction 2. Nuclear scattering - basic theory 3. Nuclear scattering by crystals 4. Correlation functions in nuclear scattering 5. Scattering by liquids 6. Neutron optics 7. Magnetic scattering - basic theory 8. Scattering from magnetically ordered crystals 9. Polarisation analysis Appendices Solutions to examples Index.
Crossing Borders: Time, Memory, and the Construction of Identity in Song of the Exile
This article analyzes the construction of memory in Ann Hui's Song of the Exile as it intersects with issues of cultural identity, national allegory, and women's autobiographies.