Abstract
ClassicalMolecularDynamics(MD)simulationscharacterizingdislocationsandradiationdamagetypicallytreat105-107atoms.Firstprinciplestechniquesemployedtounderstandsystemsatanatomisticlevelarenotpracticalforsuchlargesystemsconsistingofmillionsofatoms.Wepresentanecientcoarsegrained(CG)approachtocalculatelocalelectronicandmagneticpropertiesoflargeMD-generatedstructuresfromthe rstprinciples.LocalatomicmagneticmomentsincrystallineFeareperturbedbythepresenceofradiationgeneratedvacanciesandinterstitials.Thee ectsaremostpronouncednearthedefectcoresanddecayslowlyasthestrain eldofthedefectsdecreasewithdistance.WedeveloptheCGtechniquebasedontheLocallySelf-consistentMultipleScattering(LSMS)methodthatexploitsthenear-sightednessoftheelectronGreenfunction.TheatomicpositionsweredeterminedbyMDwithanembeddedatomforce eld.Thelocalmomentsintheneighborhoodofthedefectcoresarecalculatedwith rst-principlesbasedonfulllocalstructureinformation.Atomsintherestofthesystemaremodeledbyrepresentativeatomswithapproximatedproperties.Thecalculationsresultinlocalmomentsnearthedefectcenterswith rst-principlesaccuracy,whilecapturingcoarse-graineddetailsoflocalmomentsatgreaterlengthscales.ThisCGapproachmakestheselargescalestructuresamenableto rstprinciplesstudy.
