Distribution Mapping
Chemical tracking agents consisting of stable oxygen isotopes enable the precise mapping of oxygen movement and exchange within solid oxides and across gas-solid interfaces. An isotopic oxygen tracer such as oxygen 18 provides a detectable signal that is chemically identical to the common isotope. Researchers use these tracers to determine diffusion coefficients and surface exchange rates without altering the chemical state of the sample or the thermodynamic equilibrium of the system.
Exchange Rate
Surface reactions dictate how quickly the tracer enters the solid from the surrounding atmosphere. The surface exchange coefficient describes this rate and is influenced by the presence of catalysts or surface defects. Understanding this parameter is necessary for the development of fuel cell electrodes and oxygen sensors.
Analytical Resolution
Separation of the tracer signal from the background requires high mass resolution to avoid interference from molecules with similar weights. Modern instruments can resolve the isotope distribution with precision. The accuracy of the final diffusion model relies on the stability of the isotopic ratio during the initial loading phase.
Depth Profile
Secondary ion mass spectrometry measures the concentration of the tracer as a function of depth after a controlled annealing step. The resulting profile shows how far the isotope has penetrated into the lattice.
