Computational Prediction of Kinetic Rate Constants for Condensed Phases

ABSTRACT: A core component of aerospace manufacturing is based on cutting-edge technological applications of material design. Chemical kinetics models are vital for interpreting experimental measurements and predicting the behavior of these complex systems. Modern computational chemistry software programs are invaluable for the accurate prediction of reaction rates for kinetics models, but their use is highly specialized. We propose extending the Extensible Computational Chemistry Environment (ECCE) user interface and the Chemical Dynamics Software and Simulation (CDSSIM) website to support condensed phase chemical kinetics calculations. The result will provide simplified user access to the complementary cutting edge techniques of hybrid free energy calculations using NWChem and direct dynamics calculations using VENUS. These codes will allow the non-expert to calculate condensed phase rate constants from high-level quantum calculations, while providing a realistic prediction of their inherent errors. In Phase I, we demonstrated our software concepts on Air Force relevant test cases. In Phase II, we will integrate chemical rate constant predictions into ECCE and the CDSSIM forming the Ab initio Transition state Or Molecular dynamics Simulations for Condensed Phase Reactions (ATOMS-CPR) Toolkit, making these sophisticated calculations accessible to non-experts. BENEFIT: The proposed softwarethe Ab initio Transition state Or Molecular dynamics Simulations for Condensed Phase Reactions (ATOMS-CPR) Toolkitwill provide a unique ability to perform state-of-the-art calculations of condensed phase reaction rate constants. This work will greatly simplify the application of these advanced calculations to areas such as energetic ionic liquids as advanced propellants and explosives, which will benefit many Air Force programs. ATOMS will be the basis for upgrading chemical mechanisms used by commercial chemical modeling packages. It will be sufficiently general to apply to reactions in supercritical fluids, low earth orbit, the detonation of explosives, and biodegradation of solvents. These upgrades will impact R & D programs in multibillion-dollar industries with both military and civilian applications.