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Articles 1 - 11 of 11

Full-Text Articles in Physics

Defect Driven Magnetism In Doped Sno2 Nanoparticles: Surface Effects, Pushpa Raghani, Pankaj Kumar, Balaji Ramanujam, Alex Punnoose Mar 2016

Defect Driven Magnetism In Doped Sno2 Nanoparticles: Surface Effects, Pushpa Raghani, Pankaj Kumar, Balaji Ramanujam, Alex Punnoose

Pushpa Raghani

Magnetism and energetics of intrinsic and extrinsic defects and defect clusters in bulk and surfaces of SnO2 is investigated using first-principles to understand the role of surfaces in inducing magnetism in Zn doped nanoparticles. We find that Sn vacancies induce the largest magnetic moment in bulk and on surfaces. However, they have very large formation energies in bulk as well as on surfaces. Oxygen vacancies on the other hand are much easier to create than VSn, but neutral and VO+2 vacancies do not induce any magnetism in bulk as well as on surfaces. VO+1 induce small magnetism in bulk and …


Obtaining Mixed Ionic/Electronic Conductivity In Perovskite Oxides In A Reducing Environment: A Computational Prediction For Doped Srtio3, Suwit Suthirakun, Salai Ammal, Guoliang Xiao, Fanglin Chen, Kevin Huang, Hans Zur Loye, Andreas Heyden May 2015

Obtaining Mixed Ionic/Electronic Conductivity In Perovskite Oxides In A Reducing Environment: A Computational Prediction For Doped Srtio3, Suwit Suthirakun, Salai Ammal, Guoliang Xiao, Fanglin Chen, Kevin Huang, Hans Zur Loye, Andreas Heyden

Salai C. Ammal

No abstract provided.


Obtaining Mixed Ionic/Electronic Conductivity In Perovskite Oxides In A Reducing Environment: A Computational Prediction For Doped Srtio3, S. Suthirakun, Salai Ammal, G. Xiao, Fanglin Chen, Kevin Huang, Hans-Conrad Zur Loye, Andreas Heyden May 2015

Obtaining Mixed Ionic/Electronic Conductivity In Perovskite Oxides In A Reducing Environment: A Computational Prediction For Doped Srtio3, S. Suthirakun, Salai Ammal, G. Xiao, Fanglin Chen, Kevin Huang, Hans-Conrad Zur Loye, Andreas Heyden

Salai C. Ammal

No abstract provided.


Π-Systems As Lithium/Hydrogen Bond Acceptors: Some Theoretical Observations, Salai Ammal, P. Venuvanalingam May 2015

Π-Systems As Lithium/Hydrogen Bond Acceptors: Some Theoretical Observations, Salai Ammal, P. Venuvanalingam

Salai C. Ammal

Ab initio calculations at the Hartree–Fock and correlated levels and density functional theory calculations have been performed with 6-31++G(d,p) and 6-311++G(d,p)basis sets on LiF and HF complexes of benzene, ethylene, and acetylene. Complex binding energies have been corrected for basis set superposition error, and zero point energy corrections have been done on Hartree–Fock binding energies. Computed results indicate that the complexes exist in different conformations and among them those with π-lithium and π-hydrogen bonds are the most stable. π-lithium bonds are stronger than π-hydrogen bonds. The computed binding energies and geometry of HF complexes correlate well with the available experimental …


Chemical Interaction Of Nf3 With Si (Part Ii): Density Functional Calculation Studies, A. Endou, T. Little, A. Yamada, K. Teraishi, M. Kubo, Salai Ammal, A. Miyamoto, M. Kitajima, F. Ohuchi May 2015

Chemical Interaction Of Nf3 With Si (Part Ii): Density Functional Calculation Studies, A. Endou, T. Little, A. Yamada, K. Teraishi, M. Kubo, Salai Ammal, A. Miyamoto, M. Kitajima, F. Ohuchi

Salai C. Ammal

No abstract provided.


Density Functional Theory Study On The Electronic Structure Of N- And P-Type Doped Srtio3 At Anodic Solid Oxide Fuel Cell Conditions, S. Suthirakun, Salai Ammal, G. Xiao, Fanglin Chen, Hans-Conrad Zur Loye, Andreas Heyden May 2015

Density Functional Theory Study On The Electronic Structure Of N- And P-Type Doped Srtio3 At Anodic Solid Oxide Fuel Cell Conditions, S. Suthirakun, Salai Ammal, G. Xiao, Fanglin Chen, Hans-Conrad Zur Loye, Andreas Heyden

Salai C. Ammal

The electronic conductivity and thermodynamic stability of mixed n-type and p-type doped SrTiO3 have been investigated at anodic solid oxide fuel cell (SOFC) conditions using density functional theory (DFT) calculations. In particular, constrained ab initio thermodynamic calculations have been performed to evaluate the phase stability and reducibility of various Nb- and Ga-doped SrTiO3 at synthesized and anodic SOFC conditions. The density of states (DOS) of these materials was analyzed to study the effects of n- and p-doping on the electronic conductivity. In agreement with experimental observations, we find that the transformation from 20% Nb-doped Sr-deficient SrTiO3 to a non-Sr-deficient phase …


Adsorption Of Co2 Molecule On The (Mgo)9 And (Cao)9 Nanoclusters; A Theoretical Study, Innovative Research Publications Irp India, Fathi Hassan Bawa Apr 2015

Adsorption Of Co2 Molecule On The (Mgo)9 And (Cao)9 Nanoclusters; A Theoretical Study, Innovative Research Publications Irp India, Fathi Hassan Bawa

Innovative Research Publications IRP India

Binding configurations of CO2 on (MgO)9 and (CaO)9 cluster models are investigated by means of density functional theory model calculations. The results show that CO2 adsorbs as monodentate on MgO and CaO terrace site leads to formation of surface carbonates CO3 2- . Marginal differences in the binding stabilities between the CO2 molecule and surface O2- site were found to be significantly similar. The estimated adsorption energies are 1.47 eV and 1.52 eV at the (MgO)9 and (CaO)9 clusters, respectively. The similarity in binding energies is discussed in terms of cluster electropositivity. Adsorbed CO2, to (MgO)9 surface vibration frequencies are …


Obtaining Mixed Ionic/Electronic Conductivity In Perovskite Oxides In A Reducing Environment: A Computational Prediction For Doped Srtio3, Suwit Suthirakun, Salai Ammal, Guoliang Xiao, Fanglin Chen, Kevin Huang, Hans Zur Loye, Andreas Heyden Feb 2015

Obtaining Mixed Ionic/Electronic Conductivity In Perovskite Oxides In A Reducing Environment: A Computational Prediction For Doped Srtio3, Suwit Suthirakun, Salai Ammal, Guoliang Xiao, Fanglin Chen, Kevin Huang, Hans Zur Loye, Andreas Heyden

Kevin Huang

No abstract provided.


Rhodizonic Acid On Noble Metals: Surface Reactivity And Coordination Chemistry, Donna A. Kunkel, James Hooper, Scott Simpson, Sumit Beniwal, Katie L. Morrow, Douglas C. Smith, Kimberly Cousins, Stephen Ducharme, Eva Zurek, Axel Enders Sep 2014

Rhodizonic Acid On Noble Metals: Surface Reactivity And Coordination Chemistry, Donna A. Kunkel, James Hooper, Scott Simpson, Sumit Beniwal, Katie L. Morrow, Douglas C. Smith, Kimberly Cousins, Stephen Ducharme, Eva Zurek, Axel Enders

Axel Enders

A study of the two-dimensional crystallization of rhodizonic acid on the crystalline surfaces of gold and copper is presented. Rhodizonic acid, a cyclic oxocarbon related to the ferroelectric croconic acid and the antiferroelectric squaric acid, has not been synthesized in bulk crystalline form yet. Capitalizing on surface-assisted molecular self-assembly, a two-dimensional analogue to the well-known solution-based coordination chemistry, two-dimensional structures of rhodizonic acid were stabilized under ultrahigh vacuum on Au(111) and Cu(111) surfaces. Scanning tunneling microscopy, coupled with first-principles calculations, reveals that on the less reactive Au surface, extended two-dimensional islands of rhodizonic acid are formed, in which the molecules …


Unbiased Density Functional Solutions Of Freezing In Binary Mixtures Of Hard Or Soft Spheres, M. Valera, R. F. Bielby, F. J. Pinksi, Duane D. Johnson Jan 2001

Unbiased Density Functional Solutions Of Freezing In Binary Mixtures Of Hard Or Soft Spheres, M. Valera, R. F. Bielby, F. J. Pinksi, Duane D. Johnson

Duane D. Johnson

various size ratios, σ2/σ1, using density functional theory. The Grand Potential is minimized using an unbiased, discrete, real-space mesh that does not constrain the shape of the density, and, in many cases, leads to solutions qualitatively different from those using Gaussians and plane-waves. Besides the usual face-centered-cubic solid-solution phase for σ2/σ1≈1.0, we find a sublattice-melt phase for σ2/σ1=0.85–0.5 (where the small-sphere density is nonlocalized and multi-peaked) and the NaCl phase for σ2/σ1=0.45–0.35 (when the small-sphere density again sharpens). For a range of size ratios of soft sphere mixtures, we could not find stable nonuniform solutions. Preliminary calculations within a Modified-Weighted …


The Slater–Pauling Curve: First Principles Calculations Of The Moments Of Fe1 − C Ni C And V1 − C Fe C, Duane Johnson, F. Pinski, J. Staunton Jan 1991

The Slater–Pauling Curve: First Principles Calculations Of The Moments Of Fe1 − C Ni C And V1 − C Fe C, Duane Johnson, F. Pinski, J. Staunton

Duane D. Johnson

We have performed calculations of the electronic structure of the random substitutional alloys Fe1−c Ni c and V1−c Fe c using the spin‐polarized, self‐consistent Korringa–Kohn–Rostoker coherent‐potential approximation (KKR‐CPA) method. This is a first principles method based on spin density functionaltheory and a local spin density approximation for the exchange and correlation functional. For fcc Fe1−c Ni c , a range of volumes were considered for 0.25