title: Theoretical and experimental investigation of the thermochemistry of CrO2(OH)2(g).
abstract: In this paper, we report the results of equilibrium pressure measurements designed to identify the volatile species in the Cr-O-H system and to resolve some of the discrepancies in existing experimental data. In addition, ab initio calculations were performed to lend confidence to a theoretical approach for predicting the thermochemistry of chromium-containing compounds. Equilibrium pressure data for CrO2(OH)2 were measured by the transpiration technique for the reaction 0.5Cr2O3(s) + 0.75O2(g) + H2O(g) = CrO2(OH)2(g) over a temperature range of 573 to 1173 K at 1 bar total pressure. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to analyze the condensate in order to quantify the concentration of Cr-containing volatile species. The resulting experimentally measured thermodynamic functions are compared to those computed using B3LYP density functional theory and the coupled-cluster singles and doubles method with a perturbative correction for connected triple substitutions [CCSD(T)].
authors.affiliation: NASA Glenn Research Center, Cleveland, Ohio 44135-3191, USA. opila@nasa.gov
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Opila
authors.forename: Dwight L
authors.initials: DL
authors.lastname: Myers
authors.forename: Nathan S
authors.initials: NS
authors.lastname: Jacobson
authors.forename: Ida M B
authors.initials: IM
authors.lastname: Nielsen
authors.forename: Dereck F
authors.initials: DF
authors.lastname: Johnson
authors.forename: Jami K
authors.initials: JK
authors.lastname: Olminsky
authors.forename: Mark D
authors.initials: MD
authors.lastname: Allendorf