英语翻译

TheDIPmoleculesadsorbedatthestepedgesaligntheirlongmolecularaxisparalleltothestepdirectionandconsequentlyformrowsinahead-to-tailconfiguration.Incontrast,theadsorptionatthereconstructionelbowsdoesnotgiveclearevidenceofanypreferredmolecularorientation.Uponfurthergrowthofthenuclei,noorderisdevelopedamongthemolecules.Thisisasignatureofthelowintermolecularinteractions,asexpectedfromtheabsenceoffunctionalgroupswiththepotentialtoformH-bondsorgiverisetoanyotherinteractionsstrongerthanthevanderWaalscontribution.OnlyinlargeDIPassembliesextendingovermorethan100nm2do

wefindalongrangeorderedstructure.Adiscretenumberofrotationaldomainsisobserved,evidencingtheroleofthesubstrateastemplatedirectingthemolecularordering.Interestingly,thedifferentdomainsarenotseparatedbyabruptboundariesbutoftenfollowagradualtransitionamongthedifferentorientations.ThiscanbeobservedinFigure1a(whichshowsthreedifferentdomains)betweenthedomainsnumbered#2and#3.Thisistheproductofweakandsmoothinteractionpotentials(bothmolecule-substrateandmolecule-molecule)intheseorganicsystems,whichallowamuchhigheraccommodationofstrainthanisgenerallyknownfrominorganicmaterials.ThereconstructionoftheunderlyingAu(111)surfaceremainsvisiblebelowtheDIPlayer,whichisaconsequenceoftheweakmolecule-substrateinteraction.Inotherwords,themoleculesubstrateinteractions(vanderWaals)areontheonehandtooweaktoaffecttheAu(111)surfacereconstructionbut,ontheotherhand,strongenoughtodictatetheepitaxialgrowthoftheorganicoverlayer.Nevertheless,theobservationthatmanyofthebordersoftheseDIPassembliesfollowthecorrugationlinesoftheherringbonereconstruction(asshownforexamplebytwodashedlinesinFigure1a)revealsanon-negligibleenergeticbarrierforthegrowthprocesses(i.e.,diffusionorincorporationontothe2Dmolecularcrystalsites)acrosstheselines.