Computation of Highly Excited Molecular Spectra

Radiation-transport (RT) codes constitute the core component of the target, plume, background, and atmospheric signature models utilized by MDA and virtually every other government agency and commercial company involved in developing optically-based weapons, surveillance, and remote sensing systems. Critical to the accuracy and range of application of RT codes are the accuracy and completeness of their companion molecular spectral properties databases, e.g., HITRAN, HITEMP, SIRRM. These databases are incomplete and, in many spectral regions, are of insufficient accuracy for many applications. To address this problem Spectral Sciences, Inc. has successfully demonstrated in Phase I the potential of an innovative high-temperature spectral parameter modeling approach. Our approach, dubbed CHEMS (Computation of Highly Excited Molecular Spectra), uses classical dynamics to model the absorption by the high density of spectral lines found at high temperature, where lines blend together to form a continuum that can be described at a much lower spectral resolution. In Phase II we propose to build a complete CHEMS spectral database generation capability by implementing a general version of CHEMS integrated with a spectral line generation approach. We shall also generate the first version of the HITEMP-CHEMS database, merging HITEMP lines and CHEMS cross sections.