Search results for "electron-density critical points"

showing 1 items of 1 documents

Electron-density critical points analysis and catastrophe theory to forecast structure instability in periodic solids

2018

The critical points analysis of electron density,i.e. ρ(x), fromab initiocalculations is used in combination with the catastrophe theory to show a correlation between ρ(x) topology and the appearance of instability that may lead to transformations of crystal structures, as a function of pressure/temperature. In particular, this study focuses on the evolution of coalescing non-degenerate critical points,i.e. such that ∇ρ(xc) = 0 and λ1, λ2, λ3≠ 0 [λ being the eigenvalues of the Hessian of ρ(x) atxc], towards degenerate critical points,i.e. ∇ρ(xc) = 0 and at least one λ equal to zero. The catastrophe theory formalism provides a mathematical tool to model ρ(x) in the neighbourhood ofxcand allo…

Hessian matrixElectron densitycatastrophe theory010504 meteorology & atmospheric sciencesCondensed Matter Physic010502 geochemistry & geophysics01 natural sciencesBiochemistryInstabilityInorganic Chemistrysymbols.namesakeStructural BiologyAb initio quantum chemistry methodsGeneral Materials Sciencephase/state transitions in crystalPhysical and Theoretical Chemistryphase/state transitions in crystalsEigenvalues and eigenvectors0105 earth and related environmental sciencesPhysicsab initio calculationelectron-density critical pointCondensed matter physicsab initio calculationsDegenerate energy levelsCondensed Matter PhysicsGibbs free energyelectron-density critical points catastrophe theory phase/state transitions in crystals ab initio calculations.symbolsMaterials Science (all)Catastrophe theoryelectron-density critical points
researchProduct