title: Interplay of hydrogen-bond and coordinate covalent-bond interactions in self-assembly of NH3 molecules on the Si(001) surface.
abstract: An exchange of hydrogen-bond and coordinate covalent-bond (dative-bond) interactions is found to play a critical role in the self-assembly of NH3 molecules on the Si(001) surface. An NH3 molecule in the height of approximately 3-10 A above the surface is attracted toward the preadsorbed NH2 moiety through the long-range H-bond interaction. Within approximately 3 A, the H-bond interaction becomes repulsive, and instead the dative bond with the buckled-down Si atom governs the adsorption process. The interplay of the two interactions induces the clustering and the zigzag feature of the dissociatively adsorbed NH3 molecules on the Si(001) surface.
authors.affiliation: Korea Research Institute of Standards and Science, P.O. Box 102, Yuseong, Daejeon 305-600, Korea. yongsung.kim@kriss.re.kr
authors.forename: Yong-Sung
authors.initials: YS
authors.lastname: Kim
authors.forename: Ja-Yong
authors.initials: JY
authors.lastname: Koo
authors.forename: Hanchul
authors.initials: H
authors.lastname: Kim