scholarly journals ACCURATE, ANALYTIC, EMPIRICAL POTENTIALS AND BORN-OPPENHEIMER BREAKDOWN FUNCTIONS FOR THE X(11Σ)-STATES OF BeH, BeD, and BeT

2014 ◽  
Author(s):  
Nikesh Dattani ◽  
Staszek Welsh
Keyword(s):  
Empirical Potentials

scholarly journals Phlogopite-pargasite coexistence in an oxygen reduced spinel-peridotite ambient

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Costanza Bonadiman ◽  
Valentina Brombin ◽  
Giovanni B. Andreozzi ◽  
Piera Benna ◽  
Massimo Coltorti ◽  
...  
Keyword(s):  
Oxygen Fugacity ◽  
Upper Mantle ◽  
Mantle Xenoliths ◽  
Spinel Peridotite ◽  
Simultaneous Formation ◽  
Empirical Potentials ◽  
Elastic Data ◽  
Mineralogical Study ◽  
Semi Empirical ◽  
T Locus

AbstractThe occurrence of phlogopite and amphibole in mantle ultramafic rocks is widely accepted as the modal effect of metasomatism in the upper mantle. However, their simultaneous formation during metasomatic events and the related sub-solidus equilibrium with the peridotite has not been extensively studied. In this work, we discuss the geochemical conditions at which the pargasite-phlogopite assemblage becomes stable, through the investigation of two mantle xenoliths from Mount Leura (Victoria State, Australia) that bear phlogopite and the phlogopite + amphibole (pargasite) pair disseminated in a harzburgite matrix. Combining a mineralogical study and thermodynamic modelling, we predict that the P–T locus of the equilibrium reaction pargasite + forsterite = Na-phlogopite + 2 diopside + spinel, over the range 1.3–3.0 GPa/540–1500 K, yields a negative Clapeyron slope of -0.003 GPa K–1 (on average). The intersection of the P–T locus of supposed equilibrium with the new mantle geotherm calculated in this work allowed us to state that the Mount Leura xenoliths achieved equilibrium at 2.3 GPa /1190 K, that represents a plausible depth of ~ 70 km. Metasomatic K-Na-OH rich fluids stabilize hydrous phases. This has been modelled by the following equilibrium equation: 2 (K,Na)-phlogopite + forsterite = 7/2 enstatite + spinel + fluid (components: Na2O,K2O,H2O). Using quantum-mechanics, semi-empirical potentials, lattice dynamics and observed thermo-elastic data, we concluded that K-Na-OH rich fluids are not effective metasomatic agents to convey alkali species across the upper mantle, as the fluids are highly reactive with the ultramafic system and favour the rapid formation of phlogopite and amphibole. In addition, oxygen fugacity estimates of the Mount Leura mantle xenoliths [Δ(FMQ) = –1.97 ± 0.35; –1.83 ± 0.36] indicate a more reducing mantle environment than what is expected from the occurrence of phlogopite and amphibole in spinel-bearing peridotites. This is accounted for by our model of full molecular dissociation of the fluid and incorporation of the O-H-K-Na species into (OH)-K-Na-bearing mineral phases (phlogopite and amphibole), that leads to a peridotite metasomatized ambient characterized by reduced oxygen fugacity.

scholarly journals Empirical potentials for rovibrational energy transfer of hydrogen fluoride in collisions with argon

2001 ◽  
Vol 115 (10) ◽  
pp. 4573-4585 ◽  
Author(s):  
Robert M. Shroll ◽  
Lawrence L. Lohr ◽  
John R. Barker
Keyword(s):  
Energy Transfer ◽  
Hydrogen Fluoride ◽  
Empirical Potentials

scholarly journals Inconsistencies in modelling interstitials in FeCr with empirical potentials

2016 ◽  
Vol 121 ◽  
pp. 204-208 ◽  
Author(s):  
T.P.C. Klaver ◽  
E. del Rio ◽  
G. Bonny ◽  
S.M. Eich ◽  
A. Caro
Keyword(s):  
Empirical Potentials

Modelling transition metal surfaces with empirical potentials

1994 ◽  
Vol 304 (1-2) ◽  
pp. 223-236 ◽  
Author(s):  
Julia Uppenbrink ◽  
Roy L Johnston ◽  
John N Murrell
Keyword(s):  
Transition Metal ◽  
Metal Surfaces ◽  
Empirical Potentials ◽  
Transition Metal Surfaces

scholarly journals A confining quark model and new gauge symmetry

2014 ◽  
Vol 29 (22) ◽  
pp. 1450120 ◽  
Author(s):  
Jong-Ping Hsu
Keyword(s):  
Gauge Symmetry ◽  
Quark Model ◽  
Power Counting ◽  
Gauge Fields ◽  
Linear Potential ◽  
Field Equations ◽  
Color Charge ◽  
Gauge Bosons ◽  
Gauge Transformations ◽  
Empirical Potentials

We discuss a confining model for quark–antiquark system with a new color SU3 gauge symmetry. New gauge transformations involve non-integrable phase factors and lead to the fourth-order gauge field equations and a linear potential. The massless gauge bosons have non-definite energies, which are not observable because they are permanently confined in quark systems by the linear potential. We use the empirical potentials of charmonium to determine the coupling strength of the color charge gs and find [Formula: see text]. The rules for Feynman diagrams involve propagators with poles of order 2 associated with new gauge fields. The confining quark model may be renormalizable by power counting and compatible with perturbation theory.

Molecular Dynamics Studies of Defects in Si

1990 ◽  
Vol 209 ◽  
Author(s):  
M.S. Duesbery ◽  
D.J. Michel ◽  
Efthimios Kaxiras ◽  
B. Joos
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamic Simulation ◽  
Experimental Evidence ◽  
Dynamic Simulation ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Recent Literature ◽  
Empirical Potentials ◽  
Generalized Stacking Fault ◽  
Generalized Stacking Fault Energy

ABSTRACTThe efficacy of three modern empirical potentials in the molecular dynamic simulation of the configurations, energies and mobility of dislocation cores and their excitations is assessed in the light of recent literature. The results are found to be inconsistent both between different potentials and with experimental evidence. It is argued that the discrepancies are rooted in the limited databases which have been used in the construction of empirical potentials. The reason for the discrepancies is demonstrated by comparing empirical and density functional calculations of the generalized stacking fault energy.

An anisotropic dressed pairwise potential model for the adsorption of noble gases on boron nitride sheets

2022 ◽  
Author(s):  
Chris John ◽  
Rotti Srinivasamurthy Swathi
Keyword(s):  
Boron Nitride ◽  
Large Scale ◽  
Potential Model ◽  
Noble Gases ◽  
Large Scale Systems ◽  
Pairwise Potential ◽  
Empirical Potentials

Development of empirical potentials with accurate parameterization is indispensable while modeling large-scale systems. Herein, we report accurate parameterization of an anisotropic dressed pairwise potential model (PPM) for probing the adsorption...

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