Molecular dynamics study of organic nanostructures and metallic nanowires

Author(s)

Fernando Sato

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin
• Defense date: 2007-02-28

Examining board members

Douglas Soares Galvão; José Pedro Rino; David Lima Azevedo; Bernardo Laks; Maurice de Koning

• Advisor: Douglas Soares Galvão

Abstract

In this work we use tools of computational physics to describe the structural and formation behavior of metallic nanowires (i ) and an organic structure on metallic surface (ii ). Both subjects had been developed under computational physics point of view and compared to specific experimental data from our close collaborations with experimental and theoretical groups. In this part of the work we developed a methodology for systematic study of the formation of metallic nanowires (i ) from clusters composed by pure atoms (Au, Ag and Cu) and from bi-metallic alloys (Au-Ag). The methodology was based on the Newton equations of motion (traditional method of molecular dynamics) together with a parametrized potential of quantum origin, named Tight-binding potential with second moment approximations (TB-SMA). With the developed methodology it was possible to carry out a statistical study of suspended linear atomic chains formation from clusters and to predict new structures and defects, stacking faults, among others. We also studied aspects of the geometry of an organic molecule called Violet Lander (VL) (ii ) with classic and semi-empirical methods in vacuum and also deposited over copper [110]. The VL is one of molecules of the Lander molecules class. The great relevance of this part of the work is because we addressed and explained the rst non-biological lock-key eect in the experimental and theoretical environment. Both the works have a great nanoscience appeal, being one of its bases. It will have great importance in future applications of nanotechnology as electric contacts and organic-metallic interaction based devices (AU)