Thermodynamics Modeling for Actinide Monocarbides and Mononitrides from First Principles

The high-temperature thermodynamical properties for the actinide monocarbides and mononitrides ThC, ThN, UC, UN, PuC, and PuN are calculated from first-principles electronic-structure theory. The electronic structure is modeled with density-functional theory (DFT) and is fully relativistic, including the spin-orbit interaction. Furthermore, the DFT is extended to account for orbital–orbital interactions, by means of a parameter-free orbital-polarization (OP) technique, that has proven to be essential for the 5f electrons in plutonium. Strong anharmonicity and the temperature dependence of the lattice vibrations are captured with the self-consistent ab initio lattice dynamics (SCAILD) method. The calculated free energies and heat capacities are compared to published results from quasi-harmonic (QH) theory, and experiments, where available. For the uranium and plutonium compounds, we make use of CALPHAD assessments to help evaluate the theory. Generally, our anharmonic relativistic approach compares well with both CALPHAD and experiments. For the thorium compounds, our theory is in good accord with QH modeling of the free energy at lower temperatures but for the heat capacity the comparison is less favorable.

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Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

Canadian Journal of Physics ◽

10.1139/p06-008 ◽

2006 ◽

Vol 84 (2) ◽

pp. 115-120 ◽

Cited By ~ 3

Author(s):

G Y Gao ◽

K L Yao ◽

Z L Liu

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Pseudopotential Calculations ◽

Correlation Potential ◽

Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

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First-principles study of static displacements in Fe-Pd magnetic shape-memory alloys

MRS Proceedings ◽

10.1557/proc-1200-g04-04 ◽

2009 ◽

Vol 1200 ◽

Cited By ~ 1

Author(s):

Markus E. Gruner

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Magnetic Shape Memory ◽

Magnetic Shape Memory Alloys ◽

Functional Theory ◽

Lennard Jones ◽

Theory Comparison

AbstractThis contribution reports static ionic displacements in ferromagnetic disordered Fe70Pd30 alloys obtained by relaxation of the ionic positions of a 108-atom supercell within the framework of density functional theory. Comparison with a simple statistical model based on Lennard-Jones pair interactions reveals that these displacements are significantly larger than can be explained by the different sizes of the elemental constituents. The discrepancies are presumably related to collective displacements of the Fe atoms. Corresponding distortions are experimentally observed for ordered Fe3Pt and predicted by first-principles calculations for all ordered Fe-rich L12 alloys with Ni group elements and originate from details of the electronic structure at the Fermi level.

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First-principles insights into ammonia decomposition on MoN (0001) surface

New Journal of Chemistry ◽

10.1039/d1nj02421c ◽

2021 ◽

Author(s):

kun yuan ◽

pengju hao ◽

Xiaolin Li ◽

Yang Zhou ◽

jiangbo zhang ◽

...

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

Surface Energy ◽

Geometric Structure ◽

First Principles ◽

Density Functional ◽

Slab Model ◽

Ammonia Adsorption ◽

Functional Theory ◽

Dehydrogenation Mechanism

Density functional theory (DFT) and periodic slab model were used to study the geometric structure, electronic structure and dehydrogenation mechanism of ammonia adsorption on MoN (0001) surface. The surface energy...

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Tunable electronic structure and magnetic moment in C2N nanoribbons with different edge functionalization atoms

Physical Chemistry Chemical Physics ◽

10.1039/c7cp01359k ◽

2017 ◽

Vol 19 (23) ◽

pp. 15021-15029 ◽

Cited By ~ 7

Author(s):

Yusheng Wang ◽

Nahong Song ◽

Min Jia ◽

Dapeng Yang ◽

Chikowore Panashe ◽

...

Keyword(s):

Density Functional Theory ◽

Magnetic Properties ◽

Electronic Structure ◽

Magnetic Moment ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

Electronic And Magnetic Properties

First principles calculations based on density functional theory were carried out to study the electronic and magnetic properties of C2N nanoribbons (C2NNRs).

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A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITE ZnO BY FIRST PRINCIPLES

Modern Physics Letters B ◽

10.1142/s0217984909020540 ◽

2009 ◽

Vol 23 (19) ◽

pp. 2339-2352 ◽

Cited By ~ 6

Author(s):

LI BIN SHI ◽

SHUANG CHENG ◽

RONG BING LI ◽

LI KANG ◽

JIAN WEI JIN ◽

...

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

Band Structure ◽

Valence Band ◽

Density Of States ◽

First Principles ◽

Density Functional ◽

Functional Theory ◽

Electron Density Difference ◽

Different Strains

Density of states and band structure of wurtzite ZnO are calculated by the CASTEP program based on density functional theory and plane-wave pseudopotential method. The calculations are carried out in axial and unaxial strains, respectively. The results of density of states in different strains show that the bottom of the conduction band is always dominated by Zn 4s, and the top of valence band is always dominated by O 2p. The variation of the band gap calculated from band structure is also discussed. In addition, p-d repulsion is used in investigating the variation of the top of the valence band in different strains and the results can be verified by electron density difference.

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First Principles Calculations of Electronic Structure and Optical Properties of Cu-Doped SnS2

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.373-375.1965 ◽

2013 ◽

Vol 373-375 ◽

pp. 1965-1969

Author(s):

Kun Nan Qin ◽

Ling Zhi Zhao ◽

Yong Mei Liu ◽

Fang Fang Li ◽

Chao Yang Cui

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Optical Absorption Coefficient ◽

Impurity Level ◽

First Principles Calculations ◽

Absorption Region ◽

Functional Theory ◽

The Density Functional Theory

The electronic structure and optical properties of Cu-doped SnS2with Sn-substituted content of 0, 12.5 and 37.5 at.% were successfully calculated by the first principles plane-wave pseudopotentials based on the density functional theory. It is found that the intermediate belts appear near the Fermi level and the energy band gap becomes narrower after the doping of the Cu atoms. The absorption peaks show a remarkable redshift and the absorption region broadens relatively after introducing acceptor impurity level. When Sn atoms of 37.5 at% were substituted by Cu, the optical absorption coefficient is significantly improved in the frequency range below 5.58 eV and over 8.13 eV.

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Electronic Structure and Hydrogen Desorption in NaAlH4

MRS Proceedings ◽

10.1557/proc-837-n2.5 ◽

2004 ◽

Vol 837 ◽

Cited By ~ 1

Author(s):

S. Li ◽

P. Jena ◽

C. M. Araujo ◽

R. Ahuja

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Metal Hydrides ◽

Hydrogen Desorption ◽

Light Metal ◽

First Principles Calculations ◽

Functional Theory ◽

Design And Synthesis

ABSTRACTFirst principles calculations based on gradient corrected density functional theory are carried out to understand the electronic structure and mechanisms responsible for desorption of hydrogen from Ti doped and vacancy containing sodium-alanate (NaAlH4). The energy necessary to remove a hydrogen atom from Ti doped NaAlH4 is significantly smaller than that from pristine NaAlH4 irrespective of whether Ti substitutes the Na or the Al site. However, the presence of Na and Al vacancies is shown to play an even more important role: The removal of hydrogen associated with both Na and Al vacancies is found to be exothermic. It is suggested that this role of vacancies can be exploited in the design and synthesis of complex light metal hydrides suitable for hydrogen storage.

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Electronic Structure, Effective Masses and Optical Properties of Monoclinic HfO2 from First-Principles Calculations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.216.341 ◽

2011 ◽

Vol 216 ◽

pp. 341-344 ◽

Cited By ~ 2

Author(s):

Qi Jun Liu ◽

Zheng Tang Liu ◽

Li Ping Feng

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

Band Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

Effective Masses ◽

Indirect Band Gap ◽

Calculated Equilibrium

Electronic structure, effective masses and optical properties of monoclinic HfO2were studied using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated equilibrium lattice parameters are in agreement with the previous works. From the band structure, the effective masses and optical properties are obtained. The calculated band structure shows that monoclinic HfO2has indirect band gap and all of the effective masses of electrons and holes are less than that of a free electron. The peaks position distributions of imaginary parts of the complex dielectric function have been explained according to the theory of crystal-field and molecular-orbital bonding.

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ELECTRONIC STRUCTURE OF K0.8Fe2Se2 FROM DENSITY FUNCTIONAL THEORY GW METHOD SIMULATION

International Journal of Modern Physics B ◽

10.1142/s0217979213620178 ◽

2013 ◽

Vol 27 (15) ◽

pp. 1362017

Author(s):

LIUXI TAN ◽

RUI GUO ◽

SHIZHONG YANG ◽

EBRAHIM KHOSRAVI ◽

GUANG-LIN ZHAO ◽

...

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

Electric Dipole ◽

First Principles ◽

Density Functional ◽

Lattice Distortion ◽

The Novel ◽

Functional Theory ◽

Density Analysis ◽

Iron Based

First principles density functional theory — based (GW) method — was used to simulate the electronic structure of the novel iron-based superconductor K 0.8 Fe 2 Se 2. The calculated band gap of K 0.8 Fe 2 Se 2 at the Γ point is 0.15 eV, which is significantly lower than the 0.61 eV of vacancy free crystal KFe 2 Se 2. The d-orbital of Fe atom is overlapped with the p-orbital of Se atom. Charge density analysis shows strong lattice distortion and vacancy related electric dipole and quadruple near the K vacancy. The reflectivity is anisotropic in three coordinate directions.

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Graphene sheet with periodic vacancy: A first principles study

Physica Scripta ◽

10.1088/1402-4896/ac40d7 ◽

2021 ◽

Author(s):

Deepti Maikhuri ◽

Jaiparkash Jaiparkash ◽

Haider Abbas

Keyword(s):

Density Functional Theory ◽

Magnetic Properties ◽

Electronic Structure ◽

Band Gap ◽

Graphene Sheet ◽

First Principles ◽

Density Functional ◽

Computational Analysis ◽

Functional Theory ◽

First Principles Study

Abstract We present a comprehensive first-principles study of the electronic structure of graphene sheet with periodic vacancy. We report the structural, electronic, and magnetic properties of the graphene sheet with periodic vacancy that possess 48 C & 28 H atoms. Computational analysis based on density functional theory predicts that the periodic vacancy can modulate the properties of graphene sheet. Results show that periodic vacancies lead to the manipulation of band gap & could be utilized to tailor the electronic properties of the sheet. Also, it is found that, the graphene sheet with periodic vacancy is non-magnetic in nature.

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