2,564 research outputs found
Chemistry in One Dimension
We report benchmark results for one-dimensional (1D) atomic and molecular
systems interacting via the Coulomb operator . Using various
wavefunction-type approaches, such as Hartree-Fock theory, second- and
third-order M{\o}ller-Plesset perturbation theory and explicitly correlated
calculations, we study the ground state of atoms with up to ten electrons as
well as small diatomic and triatomic molecules containing up to two electrons.
A detailed analysis of the 1D helium-like ions is given and the expression of
the high-density correlation energy is reported. We report the total energies,
ionization energies, electron affinities and other interesting properties of
the many-electron 1D atoms and, based on these results, we construct the 1D
analog of Mendeleev's periodic table. We find that the 1D periodic table
contains only two groups: the alkali metals and the noble gases. We also
calculate the dissociation curves of various 1D diatomics and study the
chemical bond in H, HeH, He, H, HeH and
He. We find that, unlike their 3D counterparts, 1D molecules are
primarily bound by one-electron bonds. Finally, we study the chemistry of
H and we discuss the stability of the 1D polymer resulting from an
infinite chain of hydrogen atoms.Comment: 27 pages, 7 figure
Uniform Electron Gases. II. The Generalized Local Density Approximation in One Dimension
We introduce a generalization (gLDA) of the traditional Local Density
Approximation (LDA) within density functional theory. The gLDA uses both the
one-electron Seitz radius \rs and a two-electron hole curvature parameter
at each point in space. The gLDA reduces to the LDA when applied to the
infinite homogeneous electron gas but, unlike the LDA, is is also exact for
finite uniform electron gases on spheres. We present an explicit gLDA
functional for the correlation energy of electrons that are confined to a
one-dimensional space and compare its accuracy with LDA, second- and
third-order M{\o}ller-Plesset perturbation energies and exact calculations for
a variety of inhomogeneous systems.Comment: 26 pages, 2 figures, accepted for publication in Journal of Chemical
Physic
New Records of Cyperaceae and Juncaceae from the Yukon Territory
Two new species of Cyperaceae are reported, viz., Carex hoodii, and Eleocharis elliptica. Also, range extensions for eight species of Carex, Eriophorum, and Juncus are listed
Comparative study of hormonal counterregulation during GCIIS-guided hypoglycemia tests using human Proinsulin and Human Insulin (recombinant DNA)
Schlechte Scanvorlage
Comparitive Study of Hormonal Counterregulation during GCIIS-Guided Insulin Hypoglycemia Tests using Human Insulin (Recombinant DNA) and Pork Insulin
Comparing teacher roles in Denmark and England
This article reports the findings of a comparative study of teaching in Denmark and England; its broader aim is to help develop an approach for comparing pedagogy. Lesson observations and interviews identified the range of goals towards which teachers in each country worked and the actions these prompted. These were clustered using the lens of Bernsteinâs pedagogic discourse (1990; 1996) to construct teacher roles which provided a view of pedagogy. Through this approach we have begun to identify variations in pedagogy across two countries. All teachers in this study adopted a variety of roles; of significance was the ease with which competent English teachers moved between roles. The English teachers observed adopted roles consistent with a wider techno-rationalist discourse. There was a greater subject emphasis by Danish teachers whose work was set predominantly within a democratic humanist discourse, whilst the English teachers placed a greater emphasis on applied skills
Glucose-Insulin-Potassium Therapy Guided by a Glucose-Controlled Insulin Infusion System in Acute Myocardinal Infarction
Keine Wirkungsunterschiede zwischen biosynthetischem Humaninsulin (BHI) und Schweineinsulin (PI) im GCIIS-gesteuerten InsulinhypoglykÀmietest (IHT)
Vergleich der hormonellen und metabolischen Gegenregulation beim GCIIS-gesteuerten Insulinhypo-glykÀmietest (IHT) mit biosynthetischem Humaninsulin (BHI) und Schweineinsulin (PI)
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