Numerical Procedure to Extract Physical Properties from Raman Scattering Data in a Flow Reactor

A parameter estimation procedure was established to extract physical parameters related to chemical vapor deposition (CVD) processes, which consists of in situ experimental data collection and computational analysis. Specifically, mass-transport behavior in an up-flow cold-wall CVD reactor was monitored using in situ Raman spectroscopy. A two-dimensional axisymmetric model of the reactor was developed and combined with genetic and simplex algorithms for property estimation. The numerical procedure was unambiguously able to extract binary mass diffusivities and Raman cross sections from the same data set for the methane/nitrogen and ammonia/nitrogen cases. The procedure developed in this study is general and expected to be particularly useful in extracting diffusivities and cross sections for reaction intermediate species and kinetic parameters for complex reacting systems.