Ab initio methods and database development
Thermochemistry is essential to understanding chemical processes, but good data are often unavailable for many inorganic and organometallic systems. Consequently, we make extensive use of ab initio quantum chemistry methods to fill key gaps in the knowledge base. In particular, using a method developed at Sandia known as Bond Additivity Correction (BAC), we can obtain molecular heats of formation accurate to ± 2 – 3 kcal mol-1 in many cases. Higher levels of theory (e.g., coupled cluster calculations) are used to establish empirical corrections employed by the BAC method in cases where experimental data are lacking. This method is invaluable for studying many high-temperature systems and we now have data for literally hundreds of compounds. With DOE funding we created a web site that includes data for nearly 1,000 compounds, including many main group compounds unavailable anywhere else.
http://www.ca.sandia.gov/HiTempThermo/
The site also includes spectroscopic and structural information for each compound.
Selected publications
A. J. Skulan, I. M. B. Nielsen, C. F. Melius, and M. D. Allendorf "BAC-MP4 Predictions of Thermochemistry for Gas-Phase Antimony Compounds in the Sb-H-C-O-Cl System," J. Phys. Chem. A, 110 (2006), 5919.
Nielsen, IMB; Allendorf, MD "Thermochemistry of the chromium hydroxides Cr(OH)n, n = 2-6, and the oxyhydroxide CrO(OH)4: Ab initio predictions," J. Phys. Chem. A; 110 (2006), 4093.
A. J. Skulan, I. M. B. Nielsen, C. F. Melius, M. D. Allendorf "BAC-MP4 Predictions of Thermochemistry for Gas-Phase Indium Compounds in the In-H-C-O-Cl System," J. Phys. Chem. A 110 (2006), 281.
Allendorf, M. D.; Melius, C. F."BAC-MP4 Predictions of Thermochemistry for Gas-Phase Tin Compounds in the Sn-H-C-Cl System," J. Phys. Chem. A 109(2005), 4939.
I. M. B. Nielsen, M. D. Allendorf "High-level ab initio thermochemical data for halides of chromium, manganese, and iron," J. Phys. Chem. A, 109 (2005), 928.