MECHANISMS OF ENERGY ACCOMODATION ON CATALYTIC SURFACES

A BASIC UNDERSTANDING OF THE MECHANISMS OF SURFACE HEATING OF AIRCRAFT IS CRUCIAL TO THE DEVELOPMENT OF NEW MATERIALS WHICH REDUCE HEATING EFFECTS. THE GOAL OF THE PROPOSED RESEARCH IS THE DEVELOPMENT OF INNOVATIVE THEORETICAL APPROACHES TO GAIN AN UNDERSTANDING OF THE MICROSCOPIC MECHANISMS OF GAS/SURFACE INTERACTIONS, CHEMICAL ENERGY ACCOMMOCATION, AND SURFACE CATALYTIC REACTIONS. IN THE THEORETICAL APPROACH DESCRIBED HERE, THE COMPLEX PROCESS OF SURFACE HEATING IS BROKEN DOWN INTO ITS COMPONENTS WHICH ARESTUDIED INDEPENDENTLY WITHOUT THE COMPLICATIONS OF COMPETING PROCESSES. THE STUDIES OF THESE COMPONENTS ARE COMPRISED OF TWO PARTS: (1) CONSTRUCTION OF REALISTIC MODELSOF THE INTERACTION POTENTIALS AS A FUNCTION OF INTERNUCLEAR DISTANCES, AND (2) DYNAMICAL CALCULATIONS OF THE MOTION OF THE ATOMS USING THE POTENTIAL ENERGY SURFACES. IN PHASE I WE FOCUS ON THE RATE OF OXYGEN ATOM RECOMBINATION REACTIONS ON A METAL SURFACE. THE SPECIFIC OBJECTIVES ARE THE DEVELOPMENT OF REALISTIC INTERACTION POTENTIALS TO DESCRIBE REACTIVE GAS/SURFACE INTERACTIONS, THE IMPLEMENTATION OF NEWDYNAMICAL METHODS TO CALCULATE THE RATE OF GAS/SURFACE PROCESSES, THE ESTABLISHMENT OF THE RELIABILITY OF THE METHODS, AND THE IDENTIFICATION OF THE FEATURES OF THE SYSTEMS CONTROLLING THE RECOMBINATION RATES.