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Stone, E. J.

Publications and source records attributed to Stone, E. J..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

The yield of N/2D/ atoms in the dissociative recombination of NO/+/

The quantum yield or branching ratio of N(2D) atoms formed in the reaction e + NO(+) yields N + O was measured to be 76% plus or minus 6%. Photoionization of buffered nitric oxide by a flash lamp was studied using time-resolved atomic absorption. Atoms were produced both by direct photodissociation and by dissociative recombination, and these two effects were separated by means of SF6 as an electron scavenger.

Kley, D.↗
NASA NTRS1976

Determination of the line shapes of atomic nitrogen resonance lines by magnetic scans

A technique is given for calibrating an atomic nitrogen resonance lamp for use in determining column densities of atoms in specific states. A discharge lamp emitting the NI multiplets at 1200 A and 1493 A is studied by obtaining absorption by atoms in a magnetic field (0-2.5 T). This magnetic scanning technique enables the determination of the absorbing atom column density, and an empirical curve of growth is obtained because the atomic f-value is known. Thus, the calibrated lamp can be used in the determination of atomic column densities.

Lawrence, G. M.↗
NASA NTRS1975

Ultraviolet spectrograph using microchannel plates

An ultraviolet spectrograph was constructed using double microchannel plates as detectors at the focal plane. The photoelectron pulses were located one at a time by measuring the charge division to the ends of a resistor strip behind the microchannel plates. The system worked to 20,000 counts/sec and gave resolution exceeding 100 elements.

Lawrence, G. M.↗
NASA NTRS1975

Nonthermal rotational distribution of CO/A 1Pi/ fragments produced by dissociative excitation of CO2 by electron impact

Measurements were made of the rotational profiles of specific bands of the CO fourth-positive group (4PG). The CO 4PG bands were excited by electron impact dissociative excitation of CO2. The results are applicable to analysis of the Mariner observations of the CO 4PG in the dayglow of Mars. The results indicate that dissociative excitation of CO2 by electron impact leads to CO(A 1Pi) fragments with a rotational distribution that is highly nonthermal. The parent CO2 temperature was about 300 K in the experiment, while the fragment CO(A 1Pi) showed emission band profiles consistent with a rotational temperature greater than about 1500 K. Laboratory measurement of the reduced transmission of the hot bands by thermal CO appears to be the most direct way of determining the column density responsible for the CO(v',0) absorption of Mars.

Mumma, M. J.↗
NASA NTRS1974

Electron-impact excitation of the 3S0 and 5S0 states of atomic oxygen

The conditions of electron-impact excitation in flowing oxygen downstream from a discharge are reinterpreted. It is shown that total oxygen mass flow is not conserved as the discharge is turned on and off, even though the inlet flow rate remains constant. The total amount of gas is diminished when the discharge is turned on, apparently due to collection of atomic oxygen by the system walls. A revised total cross section is reported for the excitation of 1304-A radiation.

Stone, E. J.↗
NASA NTRS1973

Excitation of atomic nitrogen by electron impact.

Measurement of the absolute cross sections for the excitation of a number of N I multiplets by electron impact on atomic nitrogen. Two of these cross sections - 1134 and 1200 A - are found to be large, reaching 2.0 x 10 to the minus 16th and 2.5 x 10 to the minus 16th sq cm at their peaks, respectively. The presence of vibrationally excited molecular nitrogen in the discharged gas is confirmed, and its effect on the measurements is discussed. The ratio of the oscillator strengths of the 1200- and 1134-A resonance transitions is measured to be 2.6 plus or minus 0.3.

Stone, E. J.↗
NASA NTRS1972

Excitation of atomic nitrogen by electron impact

Absolute cross sections were measured for the excitation of the N I(1134, 1164, 1168, 1200, 1243, and 1743 A) multiplets by electron impact on atomic nitrogen. The presence of vibrationally excited molecular nitrogen in the discharged gas was confirmed, and its effect on the measurements is discussed. The ratio of the oscillator strengths of the 1200 and 1134 A resonance transitions is presented, as well as the branching ratio for the N I(1311/1164 A) multiplets. Striking differences in the distribution of intensity between the spectra of atomic nitrogen and molecular nitrogen excited by energetic electrons suggest an optical method for measuring the density of atomic nitrogen in the upper atmosphere.

Stone, E. J.↗
NASA NTRS1972

Excitation of the Werner bands of H2 by electron impact.

Absolute cross sections for the excitation of the Werner band system of molecular hydrogen have been measured from energy threshold to 300 eV for electron impact on molecular hydrogen. The bands were observed in emission in the wavelength region of 1100 to 1250 A. From a comparison of the measured cross sections with previously calculated transition probabilities, it is concluded that the Werner bands are suitable as the basis for relative spectral response calibration only when the bands are observed under sufficiently high resolution. The effect of the perturbation interaction between the B and C states of the hydrogen molecule was observed in the rotational intensity distribution of the Werner (3,7) and (3,6) bands.

Stone, E. J.↗
NASA NTRS1972

Electron-impact excitation of nitric oxide.

The absolute cross sections for the excitation of the nitrosyl cation Baer-Miescher bands, two nitric oxide bands, and several atomic nitrogen multiplets in the vacuum UV by electron impact on NO have been measured over an energy range extending from threshold to 300 eV. The variation of the dipole transition moment for the nitrosyl cation band system was also determined.

Stone, E. J.↗
NASA NTRS1972

Excitation of the Werner bands of H2 by electron impact

Absolute cross sections for the excitation of the H2 Werner band system were measured from energy threshold to 300 eV for electron impact on H2. The bands were observed in emission in the wavelength region 1100A to 1250A. The measured cross sections were compared with published transition probabilities, leading to the conclusion that the Werner bands are suitable as the basis for a relative spectral response calibration only when the bands are observed under sufficiently high resolution. The effect of the perturbation between the C 1Pi u and B 1 Sigma-u states of the hydrogen molecule was clearly observed in anomalies in the rotational intensity distribution in bands of the (3 v '') progression.

Stone, E. J.↗
NASA NTRS1971

Electron-impact excitation of nitric oxide

The absolute cross sections for the excitation of the NO(+) bands, two nitric oxide beta' bands, and several atomic nitrogen multiplets in the vacuum ultraviolet by electron impact on NO were measured over an energy range extending from threshold to 3000 eV. The variation of the dipole transition moment for the NO(+) band system was also determined.

Stone, E. J.↗