E. A. Ogryzlo

O2(1Σg+) relaxation in collisions. I. The influence of long range forces in the quenching by diatomic molecules

Rate constants for the quenching of O2(1Σg+) to O2(1Δg) by nine diatomic molecules have been calculated on the assumption that the relaxation results from long‐range interactions between the transition quadrupole of O2(1Σg+) and the transition dipole and quadrupole of the quenchers. The results suggest that in most cases this may be the dominant mode by which the relaxation of O2(1Σg+) is induced. With this assumption, the major channels for the quenching processes have been identified for most quenchers.

Orange chemiluminescence from NO2

A spectroscopic and kinetic investigation of the visible and near infrared luminescnece produced in a system containing nitric oxide, oxygen atoms, and nickel is presented. The emission spectrum is shown to be a continuum extending from 500 nm to beyond 900 nm with a maximum near 800 nm. The rate law governing this emission is shown to be I=k[O2(A, A′)][NO][O2]/[M], where k=7×10−14 cm3 molecule s−1, and [O2(A, A′] represents the combined concentrations of the 3Σu+ and 3Δu states of oxygen.

Kinetics of the reaction of gallium arsenide with molecular chlorine

The reaction of Cl2 with the (100) face of a GaAs single crystal was studied in the temperature range from 25 to 150 °C. The reaction was found to be first order in Cl2 at low pressures with an activation energy of 23.6 kcal. At pressures above 10 Torr it was found to reach a limiting rate with an activation energy of 14.2 kcal, attributable to the enthalpy of desorption of the GaCl3 product from this surface.

Rate constant for the deactivation of O2 (A3Σu+ by N2

Abstract A value of (9.3 ± 1.7) × 10 −15 cm 3 molecule −1 has been determined as the rate constant for the quenching of O 2 (A 3 Σ u + ) by N 2 at 25°C.

Halogen Atom Reactions. IV. Recombination into Electronically Excited States

Absolute emission intensities of the luminescence resulting from the recombination of ground‐state chlorine and bromine atoms have been measured in an effort to determine the proportion of the recombination occurring through electronically excited states. The emitting states [Cl2(3Π0+u), Br2(3Π1u), andBr2(3Π0+u)] are found to be efficiently quenched by the corresponding atomic species and the efficiency is found to be dependent on the total pressure. Direct quenching by ground‐state molecules is found to be at least 103 times less efficient. Rate constants for recombination via electronically excited states of Cl2 and Br2 are found to be ≥ 1014 and ≥ 1015 cc 1mole−1·sec−1, respectively. Luminescence is also reported from the recombination of ground‐state iodine atoms and assigned to the transition I2(3Π1u → 1Σg+).

The cooperative emission bands of “singlet” molecular oxygen

Abstract The Visible emission from a stream of O2(1Δg) molecules was observed under conditions where the steady state concentration of O2(1Σ+g was high. New bands at 5200, 4800, 4000 and 3800A were recorded and could be assigned to cooperative processes involving pairs of excited molecules in collision.

Halogen‐Atom Reactions. II. Luminescence from the Recombination of Chlorine Atoms

A spectroscopic study of an orange‐red glow from the products of electrical discharge in chlorine has resulted in an identification of the emitter as Cl2(A3II0u+). A kinetic study has provided evidence for the formation of excited molecules in this state by the preassociation of 2P3/2 chlorine atoms. Several detailed mechanisms for the reaction are discussed.

Techniques for depositing DLC films by pulsed laser ablation of organic solids

Abstract Two methods of forming diamond-like carbon films by the ablation of chrysene, violanthrone, polymethylmethacrylate, and fullerene are described. The relative effectiveness of the two techniques is compared. Deposition rates with different target materials are presented and the films formed are tested for hardness.

Rate constants for the etching of intrinsic and doped polycrystalline silicon by bromine atoms

The rate constants for the reaction of bromine atoms with intrinsic and heavily doped n+‐type polycrystalline silicon, as well as their temperature dependencies, are reported for the first time. The rate constant for intrinsic silicon is given as k=(4±2)×107 nm min−1 Torr−1e−(62±2kJ/mol)/RT and for n+‐type silicon with a phosphorus number density of 5×1018 cm−3, k=(1±1)×1011 nm min−1 Torr−1e−(62±2kJ/mol)/RT. Although the etch rates for the n+‐type silicon are 2–3 orders of magnitude larger than for intrinsic silicon at the same temperature and atom concentration, the difference in the two rate constants is due to a change in the pre‐exponential Arrhenius factor and not in the activation energy.

Quenching of O2(1Δg) by organic molecules

Abstract Rate constants for the quenching of O 2 ( 1 Δ g ) by 2,3-dimethyl-2-butene and triethylamine have been determined in a discharge-flow system when NO 2 is added to eliminate atomic oxygen from the system. The results indicate that in many previous determinations of rate constants for the quenching of O 2 ( 1 Δ g ) by organic compounds, atoms have probably led to erroneously high values.