Theadsorptionofraregases(Rg)ontheexternalsurfaceofpristineandSc-dopedC20(ScC19) nanocageisinvestigatedusingdensityfunctionaltheory(DFT).Also,time-dependentdensity functionaltheory(TD-DFT)andnaturalbondorbital(NBO)calculationsareperformedattheCAMB3LYP/6-31G(d)level.TheNBOanalysesindicatethattheadsorptionofRgmoleculeswithstudied nanocagesignificantlyaltersitselectronicnature.TheoreticalresultshaveshownthatRgisweakly adsorbedonthepristineC20,sothisnanocagecannotbeapropersensorfordetectingandsensingrare gases.Inordertoimprovepropertiesofthenanocageasapromisingsensor,Sc-dopingprocesswas investigated.Themorenegativeadsorptionenergies(Eads)ofRg/ScC19meansthatadsorptionofRg onthesurfaceofScC19isenergeticallymorefavoredthanC20andothernano-structuresasreportedin previousstudies.ItisexpectedthatsignificantchangesintheelectronicpropertiescausedbyRgmay beusedfordesigningnewsensorsfordetectionofraregases
