MOLECULAR-DYNAMICS SIMULATION OF SURFACE ORDERING IN LIQUID N-ALKANES

Anomalous structures were recently found at the liquid-vapor interface s in n-alkanes, n-alcohols, etc. In this paper, detailed surface struc ture of the liquid n-alkane is investigated by molecular dynamics simu lation. The computation is considerably accelerated by use of a simpli fied molecular model, in which detailed molecular structures of hydroc arbons are neglected; the systematic investigation of the melting and freezing of relatively large system is thereby enabled. Around the bul k melting point, an appreciable ordered monolayer is observed at the l iquid-vapor interface. The momolayer is characterized by the preferred bond orientation perpendicular to the surface normal and the accumula tion of the chain ends at the surface.