Future Needs and Directions of Surface Studies

It is our hope that this review conveys the rapid developments in surface structural chemistry during the past decade. We have attempted to describe the various techniques that are employed and the types of structural information that has been obtained from experiment. 

The theories of surface structure and bonding have been reviewed. It should be clear to the reader that surface structural chemistry is indeed a frontier area for both theorists and experimental researchers. From an experimentalists viewpoint the data base of atomic and molecular surface structures is very small at present. Most investigations have been carried out on flat, low Miller index surfaces of monatomic solids, either clean or with atomic or small molecules as adsorbates. 

The structure of clean surfaces of polyatomic solids (alloys, halides, oxides, sulfides, etc.) should be explored along with molecular solid surfaces (organic systems). More open, rough surfaces with high Miller indices should be investigated, including the structure of atoms and molecules bonded to steps and kinks on surfaces. Such sites are known to be key for some important surface chemical processes, but little is known of their structure. 

Molecular adsorbates of increasing size should be a fertile area of research. Such research could lead to the study of biological surfaces. The surface structure at solid-gas, solid-liquid, and solid-solid interfaces should be explored and compared with the results for the solid-vacuum interface. Structural properties of thin films, electrodes, and composite materials can be obtained in this way. 

Time resolved surface structure analysis can be employed for studies of order-order and order-disorder surface phase transitions, growth, and evaporation. Surface structures and their alterations could then be explored under extreme conditions of high temperature and irradiation by photons or particles. 

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