Jay A. Blauer

Quenching of NH(a 1Δ)

The rate coefficients for quenching of metastable NH(a 1Δ) by N2, H2, HF, F2, HNCO, NH3, N2H4, and He were measured. The 193 nm ArF pulsed laser photolysis of HNCO, NH3, and N2H4 produced NH(a 1Δ). Its lifetime was measured as a function of quenching species concentration by an LIF technique which made use of the a 1Δ→c 1π transition near 325 nm.

Excimer kinetics and multiline model for the electron-beam pumped XeF(B–X) laser

A physical model of the time-, temperature- and wavelength-dependent behavior of an E-beam pumped XeF(B-X) laser is developed. Correlations with published laser- and fluorescence-efficiency data, laser spectra, gain, and absorption data are discussed.

Aerosol generators for singlet oxygen production

Two aerosol generators for O2(a1Δ) production were designed, fabricated, and tested over a wide range of operating conditions. Each generator consisted of an injector assembly, a reaction chamber, and a nonmoving centrifugal phase separator, and differed from the other principally in the number of individual injector elements incorporated into the design (1 vs 5). A one‐dimensional engineering model of two‐phase reacting flow was developed and compared to the experimental aerosol performance data. Similar comparisons were also made with available data regarding the performance of generators based upon the sparger and wet wall concepts. These comparisons indicated that quenching losses in regions of two‐phase flow were heavily influenced by surface effects. The data indicated a collisional probability for quenching of O2(a1Δ) at the gas‐basic H2O2 interface in the vicinity of 2±1×10−3. The implications of the results of data correlations given herein relative to the design of compact, high energy density g...

Heat of Formation and Entropy of (BOCl)3

An experimental study of the equilibrium B2O3(l)+BCl3(g) = (BOCl)3(g) has been made by the method of transpiration in the temperature range of 536°—825°K. The enthalpy and entropy changes of the reaction in this temperature range were found to be 5.0±0.3 kcal/mole and 3.1±0.5 cal/deg/mole, respectively. The data have been interpreted to yield the heat of formation, ΔH°f695°K = 391.5±0.3 kcal/mole, and entropy, S°695°K = 124.2±0.5 cal/deg/mole, of gaseous (BOCl)3. Partial pressure studies indicate that the quantity of the monomer, BOCl, present in the temperature range under consideration is negligible.

Production and loss of CF2(3B1) in the O+C2F4 reaction

Low pressure fast flow measurements of the emission from CF2(3B1) generated in mixtures of O with C2F4 in Ar and similar measurements using the air afterglow to follow oxygen atoms were made. From measurements of the exponential decay of air afterglow emission, it is concluded that the reaction proceeds through a C2F4O* intermediary. From the intensity and time evolution of the CF2(3B1) emission it is found, contrary to existing belief, that the yield of CF2(3B1) is small (less than 1%) and its radiative lifetime is much shorter than 1 s. The overall loss of O atoms at low C2F4 densities is characterized by a rate constant of 1.2×10−12 cm3 s−1. Both NO and O2 strongly quench the CF2(3B1) while quenching the precursor much less effectively. C2F4 quenches the precursor regenerating O, but does not quench CF2(3B1) significantly.

Two-phase model of O2(1-delta) production with application to rotating disk generators

A model for the production of singlet delta oxygen, O 2 ( 1 (Delta) ), following the reaction of gaseous chlorine, Cl 2 , with liquid basic hydrogen peroxide, BHP, is described. The model includes diffusion of the Cl 2 gas into the liquid, diffusion of the hydroperoxy anions, HO - 2 , to the surface, reaction of the Cl 2 with the HO - 2 ions at a finite-rate, heterogeneous deactivation of the O 2 ( 1 (Delta) ) within the liquid, and homogeneous deactivation of the O 2 ( 1 (Delta) ) molecules in the gas. Transport equations are written for the chlorine, oxygen, and HO - 2 species concentrations in the liquid while ordinary rate equations are written for the chlorine and oxygen species in the gas. The appropriate initial and boundary conditions for these coupled, nonlinear equations are discussed. Several assumptions and approximations, justified because of the existence of several widely disparate temporal and spatial scales associated with the convection, diffusion, and reaction of Cl 2 with BHP, are discussed and applied to simplify these coupled equations.

Quenching of NF(b 1Σ) by IF, F2, and I2 from 330 to 572 K

The collisional quenching of NF(b 1Σ) by F2, IF, and I2 has been studied over the temperature range of 330 through 572 K. The extent of reaction was monitored by measurement of the emission intensity in the b→X transition near 529 nm. A laser‐induced fluorescence technique was used to monitor the concentration of the transient species IF and to estimate the gas temperature. Essentially, the data shows that IF and I2 reactively quench NF(b 1Σ) at a gas kinetic rate proportional to T1/2 while F2 quenches less effectively by a factor of 20. At 300 K, the rate constants are 1.2×10−10, 1.4×10−10, and 4.4×10−12 cm3 s−1 for IF, I2, and F2, respectively. These results are correlated with the results of others to give estimates of the product branching ratio for formation of the electronically excited halogen molecules at elevated temperatures.

Catalytic Efficiencies of H2O, D2O, NO, and HCl in the Vibrational Relaxation of HF and DF

The catalytic efficiencies of H2O, D2O, NO, and HCl in the vibrational relaxation of HF and of NO in the vibrational relaxation of DF were investigated over the temperature and total pressure ranges of 1000 to 4100°K and 0.1 to 0.3 atm, respectively. Measurements were made in an Ar diluent behind incident shock waves. The extent of vibrational excitation in HF was determined as a function of time by continuously monitoring the infrared emission intensity at 4150 ± 200 cm−1. Water appears to relax HF principally by means of a direct transfer of vibrational energy (V–V) between the collision partners. Furthermore, its collisional efficiency was found to be in fair agreement with the results reported by others for the analogous process of HCl relaxation by H2O. Nitric oxide was found to be at least an order‐of‐magnitude more efficient as a collision partner in the vibrational relaxation of HF than is known for either of the molecules N2 or O2. A small amount of data regarding the effect of HCl upon the vibra...

XeF ground state kinetics analysis.

A physical model of the temporal aspects of the ground electronic state of XeF in an e-beam pumped environment has been developed in terms of the most recent kinetic and thermochemical information available. Surprisal theory was used to interrelate the individual collision transition probabilities, including those describing promotion of molecules to the dissociation continuum. Molecular dissociation was assumed to occur solely from the continuum, the rate for which was obtained from the constraints of equilibrium. The model includes thermochemical aspects which account for the possibility of dissociation arising from thermally derived rotational excitation. The model, as developed, considerably impacts our interpretation of the phenomenon of improved laser performance at elevated temperatures. Considerable light is also shed on the physics of energy distribution among the principal operating frequencies of the laser.

Analysis of rotational nonequilibrium behavior in hydrogen fluoride/deuterium fluoride systems

A surprisal correlation of the experimental data for the V→R, T processes occurring in hydrogen fluoride/deuterium fluoride (HF/DF) chemical lasers indicates that the resulting product rotational level distributions may be very narrow. This result can be used to greatly simplify the modeling effort because a one‐to‐one correspondence between reactant and product states can be assumed. A similar analysis has also been used to correlate the published experimental results for R→R, T relaxation of HF/DF molecules. The correlation compares well with the trajectory analysis of Wilkins. Since the available experimental data for R→R, T relaxation relate to ambient conditions, the trajectory analysis temperature dependence was assumed.