C4F9 bonded to diamond (100) surface.

One surface C is bonded to C4F9 while the other saturated with F. The whole structure is optimized at Hartree-Fock Level.

Introduction

The surface properties of many materials may be significantly improved by the use of diamond coatings. Diamond films exhibit robust physical properties making possible the fabrication of long-lived cutting tools, biological implants, optical disks, lenses and windows, etc. In each of these applications, it may be desirable to modify the properties of outer surface of the diamond film itself in order to build in special properties of the protective diamond coating. It has been shown that the strong F-C bonds on diamond provide enhanced lubricity (Hsu and Turner, 1989) and enhanced stability under oxidizing conditions at elevated temperatures (Patterson, Hauge and Margrave, 1989). Recently Prof. John T. Yates' group at University of Pittsburgh have found a facile way of fluorinating diamond (100) surface by X-ray photodecomposition of perfluorinated alkyl iodides (CxF2x+1I) which produces perfluorinated alkyl radicals capable of attacking the diamond surface. In colloration with Prof. John T. Yates' group, we have carried out extensive ab initio calculations on diamond surfaces , the reconstruction, the chemical shifts upon fluorination and possible mechanisms of the photodecomposition. Our results agree very well with available experiments and provide informations for further experimental studies.