A new molecular spectroscopic database for high-temperature modeling of the spectra of molecules in the gas phase is described. This database, called HITEMP, is analogous to the HITRAN database but encompasses many more bands and transitions than HITRAN for the absorbers H2O, CO2, CO, NO, and OH. HITEMP provides users with a powerful tool for a great many applications: astrophysics, planetary and stellar atmospheres, industrial processes, surveillance, non-local thermodynamic equilibrium problems, and investigating molecular interactions, to name a few. The sources and implementation of the spectroscopic parameters incorporated into HITEMP are discussed.

HITEMP, the high-temperature molecular spectroscopic database

Many, if not most, redox reactions are coupled to proton transfers. This includes most common sources of chemical potential energy, from the bioenergetic processes that power cells to the fossil fuel combustion that powers cars. These proton-coupled electron transfer or PCET processes may involve multiple electrons and multiple protons, as in the 4 e–, 4 H+ reduction of dioxygen (O2) to water (eq 1), or can involve one electron and one proton such as the formation of tyrosyl radicals from tyrosine residues (TyrOH) in enzymatic catalytic cycles (eq 2). In addition, many multi-electron, multi-proton processes proceed in one-electron and one-proton steps. Organic reactions that proceed in one-electron steps involve radical intermediates, which play critical roles in a wide range of chemical, biological, and industrial processes. This broad and diverse class of PCET reactions are central to a great many chemical and biochemical processes, from biological catalysis and energy transduction, to bulk industrial chemical processes, to new approaches to solar energy conversion. PCET is therefore of broad and increasing interest, as illustrated by this issue and a number of other recent reviews.

/pdf/thermochemistry-of-proton-coupled-electron-transfer-reagents-v04esq6den.pdf

Thermochemistry of Proton-Coupled Electron Transfer Reagents and its Implications

A comprehensively tested H2/O2 chemical kinetic mechanism based on the work of Mueller et al. 1 and recently published kinetic and thermodynamic information is presented. The revised mechanism is validated against a wide range of experimental conditions, including those found in shock tubes, flow reactors, and laminar premixed flame. Excellent agreement of the model predictions with the experimental observations demonstrates that the mechanism is comprehensive and has good predictive capabilities for different experimental systems, including new results published subsequent to the work of Mueller et al. 1, particularly high-pressure laminar flame speed and shock tube ignition results. The reaction H + OH + M is found to be primarily significant only to laminar flame speed propagation predictions at high pressure. All experimental hydrogen flame speed observations can be adequately fit using any of the several transport coefficient estimates presently available in the literature for the hydrogen/oxygen system simply by adjusting the rate parameters for this reaction within their present uncertainties. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 566–575, 2004

https://www.princeton.edu/~combust/research/publications/H2_O2%20Mech%20(Li%20et%20al%20Int%20J%20Chem%20Kin%2036%20566%20575,%202004).pdf

An updated comprehensive kinetic model of hydrogen combustion

A detailed kinetic mechanism has been developed to simulate the combustion of H2/O2 mixtures, over a wide range of temperatures, pressures, and equivalence ratios. Over the series of experiments numerically investigated, the temperature ranged from 298 to 2700 K, the pressure from 0.05 to 87 atm, and the equivalence ratios from 0.2 to 6.

Ignition delay times, flame speeds, and species composition data provide for a stringent test of the chemical kinetic mechanism, all of which are simulated in the current study with varying success. A sensitivity analysis was carried out to determine which reactions were dominating the H2/O2 system at particular conditions of pressure, temperature, and fuel/oxygen/diluent ratios. Overall, good agreement was observed between the model and the wide range of experiments simulated. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 603–622, 2004

/pdf/a-comprehensive-modeling-study-of-hydrogen-oxidation-4urakgs38l.pdf

A comprehensive modeling study of hydrogen oxidation

Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

In a recent letter (J. Phys. Chem. A, 2001, 105,1), we argued that, although all major thermochemical tables recommend a value of (OH) based on a spectroscopic approach, the correct value is 0.5 kcal/mol lower as determined from an ion cycle. In this paper, we expand upon and augment both the experimental and theoretical arguments presented in the letter. In particular, three separate experiments (mass-selected photoionization measurements, pulsed-field-ionization photoelectron spectroscopy measurements, and photoelectron-photoion coincidence measurements) utilizing the positive ion cycle to derive the O−H bond energy are shown to converge to a consensus value of the appearance energy AE0(OH+/H2O) = 146117 ± 24 cm-1 (18.1162 ± 0.0030 eV). With the most accurate currently available zero kinetic energy photoionization value for the ionization energy IE(OH) = 104989 ± 2 cm-1, corroborated by a number of photoelectron measurements, this leads to D0(H−OH) = 41128 ± 24 cm-1 = 117.59 ± 0.07 kcal/mol. This corres...

http://tyr0.chem.wsu.edu/~kipeters/Pages/pdfs/JPC106.2727.2002.pdf

Cheuk-Yiu Ng

Papers

On the Enthalpy of Formation of Hydroxyl Radical and Gas-Phase Bond Dissociation Energies of Water and Hydroxyl