scholarly journals Calibration of 57Fe Mössbauer constants by first principles

2016 ◽  
Vol 18 (15) ◽  
pp. 10201-10206 ◽  
Author(s):  
Silvia Casassa ◽  
Anna Maria Ferrari
Keyword(s):  
Isomer Shift ◽  
Ab Initio ◽  
First Principles ◽  
Functional Approach ◽  
Basis Set ◽  
Hybrid Functional ◽  
57Fe Mössbauer ◽  
Mössbauer Isomer Shift ◽  
Quadrupolar Moment

Ab initio periodic esimate of Mössbauer isomer shift and quadrupolar moment for iron: hybrid functional approach in a GTO basis set.

Comment on “Calibration of 57Fe Mössbauer constants by first principles” Phys. Chem. Chem. Phys., 2016, 18, 10201–10206

2016 ◽  
Vol 18 (37) ◽  
pp. 26306-26309 ◽  
Author(s):  
Fernande Grandjean ◽  
Gary J. Long
Keyword(s):  
Isomer Shift ◽  
First Principles ◽  
Chem Phys ◽  
57Fe Mössbauer ◽  
Proportionality Constant ◽  
Mössbauer Isomer Shift ◽  
Phys Chem Chem Phys

The proportionality constant between the iron-57 Mössbauer isomer shift and the electron probablility density at the nucleus is reevaluated from the correct experimental isomer shifts.

57Fe Mössbauer isomer shift of pure iron and iron oxides at high pressure—An experimental and theoretical study

2021 ◽  
Vol 154 (21) ◽  
pp. 214104
Author(s):  
Jacques K. Desmarais ◽  
Wenli Bi ◽  
Jiyong Zhao ◽  
Michael H. Hu ◽  
Esen Alp ◽  
...  
Keyword(s):  
High Pressure ◽  
Isomer Shift ◽  
Iron Oxides ◽  
Pure Iron ◽  
Theoretical Study ◽  
57Fe Mössbauer ◽  
Mössbauer Isomer Shift

AB INITIO INVESTIGATION OF ELECTRONIC AND VIBRATIONAL PROPERTIES OF ZnS AND ZnSe CRYSTALS BY DIFFERENT XC-FUNCTIONALS

2009 ◽  
Vol 23 (19) ◽  
pp. 3845-3857 ◽  
Author(s):  
D. M. POPOVA ◽  
B. N. MAVRIN ◽  
A. V. SOLOV'YOV
Keyword(s):  
First Principles ◽  
Correlation Energy ◽  
Quantitative Description ◽  
Basis Set ◽  
Vibrational Properties ◽  
Hybrid Functional ◽  
Exchange Correlation ◽  
Zinc Blende ◽  
Dependent Potential ◽  
Projector Augmented Wave

Ground state properties of zinc-blende structures ZnS and ZnSe are investigated from first principles using plane wave basis, projector augmented wave method and local orbital-dependent potential, as well as a basis set of Gaussian-type functions with hybrid functionals for the approximation of exchange-correlation energy. The results of DFT calculations with the LDA, LDA+U, GGA, GGA+U, BLYP, B3P86, P3PW, BH-HP, KMLYP and B3LYP approximations are compared. It is shown that the hybrid functional B3LYP provides an accurate quantitative description of the structural, electronic and vibrational properties of ZnS and ZnSe in comparison with experimental data.

The 57Fe Mössbauer isomer shift in intermetallic compounds of iron

Physica B+C ◽  
1986 ◽  
Vol 138 (1-2) ◽  
pp. 55-62 ◽  
Author(s):  
A.M. Van der Kraan ◽  
K.H.J. Buschow
Keyword(s):  
Isomer Shift ◽  
Intermetallic Compounds ◽  
57Fe Mössbauer ◽  
Mössbauer Isomer Shift

The 57Fe Mössbauer Isomer Shift in Microdoped Monoxides

1993 ◽  
Vol 103 (1) ◽  
pp. 25-29 ◽  
Author(s):  
M.G. Smith ◽  
J.B. Goodenough
Keyword(s):  
Isomer Shift ◽  
57Fe Mössbauer ◽  
Mössbauer Isomer Shift

A first principles study of the phonon anharmonicity, electronic structure and optical characteristics of LaAlO3

2018 ◽  
Vol 1 (1) ◽  
pp. 161-180 ◽  
Author(s):  
Bahaa Ilyas ◽  
Badal Elias
Keyword(s):  
Thermal Conductivity ◽  
Electronic Structure ◽  
Ab Initio ◽  
Conversion Efficiency ◽  
First Principles ◽  
Phonon Scattering ◽  
Phonon Dispersion ◽  
Optical Spectra ◽  
Hybrid Functional ◽  
The Way

The way elementary excitations work together with their couplings and interact as condensed matter systems is very important when designing optimum energy-conversion devices. We investigated the electronic structure of LaAlO3, and we show that the bandgap insulator of LaAlO3 obtained theoretically by the hybrid functional HSE06 is an indirect 5.649eV that show a very good agreement with experimental data. The lattice constant is obtained exactly as experiment. In thermos-electric materials, the concept of conversion-efficiency (heat to electricity) is improved instantly by suppressing the phonon quasi-particles propagations that are responsible for draft macroscopic thermal transport. The material presented here for thermo-electric conversion-efficiency of cubic perovskite LaAlO3, show that it has an ultralow thermal-conductivity, while the formalism to its strong phonon scattering interactions resides mostly unclear. From the bases of Ab-initio simulations, the 4-dimensional phonon-dispersion surfaces of the cubic perovskite LaAlO3, have been mapped and we found that the origins of the ionic potential an-harmonicity being responsible for the unique behaviour and properties of LaAlO3. It is investigated that these phonon scattering arise solely from the LaAlO3 unstable electronic-structure, with its orbital interactions resulting to lattice instability similar to the ferroelectric instabilities. Our results show a microscopic insight bonding electronic-structure and phonon an-harmonicity in LaAlO3, and provides some new picture the way interactions happen between phonon–electron and phonon–phonon this lead to understand the concept of ultralow thermal-conductivity. Ab-initio calculations was performed on cubic perovskite LaAlO3 to obtain the phonon density of states (DOS) from 50 K to 5000 K, we find that the anharmonic behaviour starts around temperature limits of 500 K. The computed optical spectra were obtained using both the Beth Slapter Equation BSE and compared with the perturbed method using HSE06, optical spectra show that the inter-band transition occur precisely from the O-valence bands to the La-conduction bands throughout the low energy area. The energy-loss spectrum, optical conductivity and reflectivity and the refractive index are computed from first principles by using HSE06 hybrid functional. The optical band gap of material shows about 6.21 eV, which agrees with some cited experimental measurements.

scholarly journals Exploring Metastable States in UO2 using Hybrid Functionals and Dynamical Mean Field Theory

2021 ◽  
Author(s):  
Laura E Ratcliff ◽  
Luigi Genovese ◽  
Hyowon Park ◽  
Peter B. Littlewood ◽  
Alejandro Lopez-Bezanilla
Keyword(s):  
Field Theory ◽  
First Principles ◽  
Density Functional ◽  
Atomic Orbital ◽  
Mean Field Theory ◽  
Mean Field ◽  
Basis Set ◽  
Dynamical Mean Field Theory ◽  
Hybrid Functional ◽  
Functional Theory

Abstract A detailed exploration of the f-atomic orbital occupancy space for UO2 is performed using a first principles approach based on density functional theory (DFT), employing a full hybrid functional within a systematic basis set. Specifically, the PBE0 functional is combined with an occupancy biasing scheme implemented in a wavelet-based algorithm which is adapted to large supercells. The results are compared with previous DFT+U calculations reported in the literature, while dynamical mean field theory (DMFT) is also performed to provide a further base for comparison. This work shows that the computational complexity of the energy landscape of a correlated f-electron oxide is much richer than has previously been demonstrated. The resulting calculations provide evidence of the existence of multiple previously unexplored metastable electronic states of UO2, including those with energies which are lower than previously reported ground states.

Sign in / Sign up

Export Citation Format

Share Document