Mechanism and modeling of nitrogen chemistry in combustion

Analytical expressions are derived for the evaluation of energy gradients in the zeroth order regular approximation (ZORA) to the Dirac equation. The electrostatic shift approximation is used to avoid gauge dependence problems. Comparison is made to the quasirelativistic Pauli method, the limitations of which are highlighted. The structures and first metal-carbonyl bond dissociation energies for the transition metal complexes W(CO)6, Os(CO)5, and Pt(CO)4 are calculated, and basis set effects are investigated.

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Geometry optimizations in the zero order regular approximation for relativistic effects.

A new hybrid Hartree−Fock−density functional (HF-DF) model called the modified Perdew−Wang 1-parameter model for kinetics (MPW1K) is optimized against a database of 20 forward barrier heights, 20 r...

Adiabatic connection for kinetics

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

During the last two decades atmospheric (or high) pressure non-thermal plasmas in and in contact with liquids have received a lot of attention in view of their considerable environmental and medical applications. The simultaneous generation of intense UV radiation, shock waves and active radicals makes these discharges particularly suitable for decontamination, sterilization and purification purposes. This paper reviews the current status of research on atmospheric pressure non-thermal discharges in and in contact with liquids. The emphasis is on their generation mechanisms and their physical characteristics.

http://iopscience.iop.org/article/10.1088/0022-3727/42/5/053001/pdf

Non-thermal plasmas in and in contact with liquids

Organometallic bond dissociation energies: laser pyrolysis of iron pentacarbonyl, chromium hexacarbonyl, molybdenum hexacarbonyl, and tungsten hexacarbonyl

Collisional Quenching of CH(A), OH(A), and NO(A) in Low Pressure Hydrocarbon Flames

In uence of ambient conditions on the laser air spark

Thermally averaged cross sections σQ for collisional quenching of the A 2Σ+ state of the OH molecule have been measured near 1100 K. The OH was produced and detected in a laser pyrolysis/laser fluorescence experiment, in which a mixture of SF6, H2O2, and the collision partner M was heated by a pulsed CO2 laser. Thermal decomposition of the peroxide produces OH which is then excited by a tunable laser; the real‐time decay of the fluorescence signal at different pressures of M furnishes σQ. These σQ at elevated temperatures are generally less than the room temperature values. This result, the size of σQ, and its variation with M suggest the importance of attractive forces in the collisional quenching. The experimental results have been compared with a theoretical calculation of σQ based on multipole attractive forces with a repulsive centrifugal barrier. Good correlation is obtained for eight of the 11 quenchers studied; the experimental values of σQ for N2 and SF6 are conspicuously low.

Gregory P. Smith

Papers

Organometallic bond dissociation energies: laser pyrolysis of iron pentacarbonyl, chromium hexacarbonyl, molybdenum hexacarbonyl, and tungsten hexacarbonyl

Collisional Quenching of CH(A), OH(A), and NO(A) in Low Pressure Hydrocarbon Flames

In uence of ambient conditions on the laser air spark

Collisional quenching of A 2Σ+ OH at elevated temperatures

Low pressure flame determinations of rate constants for OH(A) and CH(A) chemiluminescence