Abstract
ClassicalMolecularDynamics(MD)simulationscharacterizingdislocationsandradiationdamagetypicallytreat105-107atoms.Firstprinciplestechniquesemployedtounderstandsystemsatanatomisticlevelarenotpracticalforsuchlargesystemsconsistingofmillionsofatoms.Wepresentanecientcoarsegrained(CG)approachtocalculatelocalelectronicandmagneticpropertiesoflargeMD-generatedstructuresfromtherstprinciples.LocalatomicmagneticmomentsincrystallineFeareperturbedbythepresenceofradiationgeneratedvacanciesandinterstitials.Theeectsaremostpronouncednearthedefectcoresanddecayslowlyasthestraineldofthedefectsdecreasewithdistance.WedeveloptheCGtechniquebasedontheLocallySelf-consistentMultipleScattering(LSMS)methodthatexploitsthenear-sightednessoftheelectronGreenfunction.TheatomicpositionsweredeterminedbyMDwithanembeddedatomforceeld.Thelocalmomentsintheneighborhoodofthedefectcoresarecalculatedwithrst-principlesbasedonfulllocalstructureinformation.Atomsintherestofthesystemaremodeledbyrepresentativeatomswithapproximatedproperties.Thecalculationsresultinlocalmomentsnearthedefectcenterswithrst-principlesaccuracy,whilecapturingcoarse-graineddetailsoflocalmomentsatgreaterlengthscales.ThisCGapproachmakestheselargescalestructuresamenabletorstprinciplesstudy.