Negative Thermal Expansion Properties and the Role of Guest Alkali Atoms in LnFe(CN)6 (Ln = Y, La) from ab Initio Calculations

2018 ◽  
Vol 122 (23) ◽  
pp. 12421-12427 ◽  
Author(s):  
Dahu Chang ◽  
Changqing Wang ◽  
Zaiping Zeng ◽  
Chunyan Wang ◽  
Fei Wang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Negative Thermal Expansion ◽  
Alkali Atoms

Scrutinizing negative thermal expansion in MOF-5 by scattering techniques and ab initio calculations

2013 ◽  
Vol 42 (6) ◽  
pp. 1996-2007 ◽  
Author(s):  
Nina Lock ◽  
Mogens Christensen ◽  
Yue Wu ◽  
Vanessa K. Peterson ◽  
Maja K. Thomsen ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Negative Thermal Expansion

Role of Thermal Expansion and Redistribution of Components on the Temperature Dependence of the Lattice Misfit in γ/γ' Superalloys

2006 ◽  
Vol 980 ◽  
Author(s):  
Oleg Kontsevoi ◽  
Yuri N. Gornostyrev ◽  
Arthur J. Freeman
Keyword(s):  
Thermal Expansion ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Temperature Dependence ◽  
Temperature Region ◽  
Lattice Misfit ◽  
Slight Variation ◽  
Relative Role ◽  
The Difference

AbstractThe relative role of thermal expansion and redistribution of alloy components in the temperature dependence of the lattice misfit in γ/γ' alloys is investigated on the basis of ab initio calculations. We show that in a wide temperature region up to approximately 0.6·Tmelt, the lattice misfit is determined by the difference in thermal expansion of γ and γ' phases and shows only a slight variation. For higher temperatures the redistribution of the major alloy components between the phases becomes a leading contribution to the lattice misfit.

scholarly journals Three-nucleon forces

2014 ◽  
Vol 23 (09) ◽  
pp. 1430015 ◽  
Author(s):  
Peter U. Sauer
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Body Problem ◽  
Many Body ◽  
Nuclear Systems ◽  
The Difference

In this paper, the role of three-nucleon forces in ab initio calculations of nuclear systems is investigated. The difference between genuine and induced many-nucleon forces is emphasized. Induced forces arise in the process of solving the nuclear many-body problem as technical intermediaries toward calculationally converged results. Genuine forces make up the Hamiltonian. They represent the chosen underlying dynamics. The hierarchy of contributions arising from genuine two-, three- and many-nucleon forces is discussed. Signals for the need of the inclusion of genuine three-nucleon forces are studied in nuclear systems, technically best under control, especially in three-nucleon and four-nucleon systems. Genuine three-nucleon forces are important for details in the description of some observables. Their contributions to observables are small on the scale set by two-nucleon forces.

Primary pyroelectric transition temperatures of binary nitrides (AlN, GaN and InN)

2019 ◽  
Vol 33 (05) ◽  
pp. 1950049
Author(s):  
Muralidhar Swain ◽  
Sushant K. Sahoo ◽  
Bijay K. Sahoo
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Negative Thermal Expansion ◽  
Polarization Field ◽  
Piezoelectric Polarization ◽  
Polarization Mechanism ◽  
Prior Literature

The primary pyroelectric transition temperature of wurtzite nitrides (AlN, GaN and InN) has been explored theoretically from their thermal properties. The spontaneous and piezoelectric polarization modifies the thermal conductivity of nitrides. The thermal conductivity [Formula: see text] as a function of temperature including and excluding the polarization mechanism predicts a transition temperature [Formula: see text] between primary and secondary pyroelectric effects. Below [Formula: see text], thermal conductivity including polarization field [Formula: see text] is lesser than thermal conductivity excluding polarization field [Formula: see text]. This is due to negative thermal expansion in binary nitrides below [Formula: see text]; however, above [Formula: see text], [Formula: see text]. [Formula: see text] is significantly contributed by piezoelectric polarization above [Formula: see text] due to thermal expansion which is the reason for the secondary pyroelectric effect. The transition temperature [Formula: see text] for AlN, GaN and InN has been predicted as 100 K, 70 K and 60 K, respectively, which fit well with the prior literature studies. This report proposes that thermal properties’ study can reveal the role of acoustic phonons in pyroelectricity.

Role of silicon vacancies in yttrium-disilicide compounds from ab initio calculations

1997 ◽  
Vol 55 (20) ◽  
pp. 13479-13484 ◽  
Author(s):  
L. Magaud ◽  
A. Pasturel ◽  
G. Kresse ◽  
J. Hafner
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio
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