Electron bombardment ion source for low energy beams.
High current electron bombardment ion source for production of low energy ion beams without metastable contamination
Dworetsky, S.↗
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Two-photon processes in the solar X-ray spectrum.
Two photon decay of metastable levels of hydrogenic and He-like ions in solar corona, depopulating via proton collisional excitation to 2p level
Smith, T. S.↗
Absorption from excited states in laser-pumped calcium.
Absorption spectra from excited metastable states in tunable dye laser pumped atomic Ca, using fast flashlamp continuum
Mcilrath, T. J.↗
Excitation of atomic hydrogen to the metasable 2 2S1/2 state by electron impact
Atomic hydrogen excitation to metastable 2 /2/ S sub 1/2 state by electron impact
Fite, W. L.↗
Energy transfer from N2/A super 3 sigma sub u/plus// as a source of O/super 1 S/ in the aurora
Nitrogen deactivation by ground state atomic oxygen resulting in metastable oxygen atom as auroral green line source
Parkinson, T. D.↗
Helium-cadmium laser parameters
He-Cd laser discharge, determining population densities and lifetimes for levels of Cd ion excited by He metastables
Hodges, D. T.↗
Quenching and radiation rates of CO /a super 3 pi/
Carbon monoxide in metastable state, considering quenching and radiative lifetime
Lawrence, G. M.↗
Observations of stellar chromospheres
Stellar chromosphere detection through H, K and metastable He lines observation, noting importance for solar physics
Zirin, H.↗
Study of excitation transfer in flowing helium afterglow pumped with a tuneable dye laser. 2: Measurement of the rate coefficient for the rotational relaxation of He2(3p (3 Pi g))
The rotational relaxation of the He2(3p(3pi g)) state is examined by optically pumping a flowing helium afterglow with a tuneable dye laser. The population of the J = 8 rotational state is enhanced by optically saturating the R sub 7 component of the transition connecting this state with the metastable He2(2s (3 Sigma u +)) molecular state. From the lifetime and yield of the Q sub 7 component, the rate coefficient for the rotational relaxation via the forbidden delta J = 1 channel is determined to be of the order of 2 x 10 to the minus 11th power cm3/sec. It is found that this represents about half of the total rate of rotational relaxation in this state.
Collins, C. B.↗
Heterogeneous nucleation of gamma prime in Al-Ag and Al-Ag /Cd or Cu/ alloys.
Results of transmission electron microscopy studies of heterogeneous nucleation of the metastable gamma prime phase were made in binary and ternary alloys of Al-5 at. % Ag, Al-4.8 at. % Ag-0.15 at. % Cd, and Al-4.8 at. % Ag-0.2 at. % Cu. Heterogeneous nucleation of gamma prime was found to be associated with four types of dislocations, regardless of the quenching treatment or alloy additions which were used. Nucleation was found to occur on: (a) jogged dislocations; (b) helical dislocations; (c) dislocation loops; (d) heterogeneous climb sources. Only one nucleation mechanism was found to be unique to the ternary alloys: that of nucleation on heterogeneous climb sources.
Passoja, D. E.↗
Characteristics of the continuous wave neutral argon laser.
Study of the characteristics of the CW neutral argon IR laser, using a variety of techniques. The output power enhancement effects of helium and chlorine gases are measured, and the reasons for the enhancement are determined. The gain is measured for the 2.397-, 2.208-, 2.062-, and 1.792-micron laser lines, using an internal cavity-loss method and a single-pass amplifier method. In addition, the saturation intensity is measured, and competition effects are studied. It is concluded that helium aids excitation of the upper laser levels by producing a significant increase in the electron temperature. Chlorine is shown to aid deexcitation of the lower laser levels by partially depopulating the metastable argon 4s levels that lie just below them.
Dauger, A. B.↗
Mass spectrometry in structural and stereochemical problems. CXCIX.
Electron-impact induced fragmentations of o-, m-, and p-hydroxyalkylphenones and their trimethylsilyl (TMS) ethers are studied by means of high-resolution mass spectrometry, metastable defocusing, and deuterium labeling of the TMS ether derivatives. A markedly increased methyl radical loss from the o-TMS ether is attributed to a proximity effect. Minor fragmentation was observed with m- and p-isomers. Significantly intense doubly-charged ions were formed from ketonic cleavage and by the loss of a TMS methyl radical. The sequence of fragmentation was found to depend on the size of the alkyl group attached to the ketone carbonyl.
Smith, G. G.↗
Absolute measurements of light emission from CO2/+/ and CO in the interaction of He/2 super 3 S/ with CO2.
A flowing afterglow has been used to produce metastable He(2 super 3 S). It is shown that when He(2 super 3 S) interacts with a diatomic or triatomic molecule, its electronic excitation energy can be transferred to electronic and vibrational excitation of the molecule. To examine this mechanism, the rates for the production of electronically excited molecules, observed spectroscopically between 190 and 750 nm in the reaction of He(2 super 3 S) with CO2, have been measured. Results are tabulated.
Wauchop, T. S.↗
Spectroscopy of dimers.
The method of Stogryn and Hirschfelder, which divides two-particle phase space into bound, metastable, and free particle parts, is applied to the statistical averages which determine the first three spectroscopic moments of 'collision-induced' far-infrared and Raman spectra. Numerical results are presented for a number of models of noble gas systems. It is shown that for some systems, but not all, dimers make important, although not necessarily well-separated, contributions to the spectrum.
Levine, H. B.↗
The electron-impact promoted fragmentation of aurone epoxides.
The mass spectra of six aurone epoxides have been rationalized with the aid of high resolution mass spectrometry and metastable ion evidence. These compounds fragment in a well defined manner and mechanisms are proposed for the formation of their characteristic ions. Some similarity was observed between the mass spectra of 6-methoxyaurone epoxide (II), 4-hydroxy-7-methoxy-3-phenylcoumarin (VII) and 7-methoxyflavonol (IX). The possibility that VII and IX are intermediates in the fragmentation of epoxide II is discussed. Thermal rearrangement of aurone epoxide II was shown to yield the corresponding flavonol IX and coumarin VII.
Brady, B. A.↗
Resonance scattering of the first positive system of N2 in the dayglow.
Rocket measurements of the differential photoelectron flux and the volume emission rate of the N2(0, 0) second positive band are used to calculate the daytime concentration of metastable A(super 3)Sigma(sub u)+ molecules, and consequently the resonance scattering contribution to the N2 first positive emission in the dayglow. The dominant source of N2 first positive emission is found to be photoelectron impact, with resonance scattering contributing only 10-20 per cent the total emission.
Feldman, P. D.↗
Artificial meteor ablation studies - Iron oxides.
Artificial meteor ablation was performed on natural minerals composed predominantly of magnetite and hematite by using an arc-heated plasma stream of air. Analysis indicates that most of the ablated debris was composed of two or more minerals. Wustite, a metastable mineral, was found to occur as a common product. The 'magnetite' sample, which was 80% magnetite, 14% hematite, 4% apatite, and 2% quartz, yielded ablated products consisting of more than 12 different minerals. Magnetite occurred in 91% of the specimens examined, hematite in 16%, and wustite in 30%. The 'hematite' sample, which was 96% hematite and 3% quartz, yielded ablated products consisting of more than 13 different minerals. Hematite occurred in 47% of the specimens examined, magnetite in 60%, and wustite in 28%. The more volatile elements (Si, P, and Cl) were depleted by about 50%. This study has shown that artificially created ablation products from iron oxides exhibit unique properties that can be used for identification.
Blanchard, M. B.↗
Force-free magnetic-field structures and their role in solar activity.
Magnetic-field structures in solar active regions are expected to be substantially force-free. A method is proposed for calculating such structures by numerical methods. The method is applied to the study of the magnetic-field pattern associated with a sunspot of one polarity surrounded by a magnetic region of opposite polarity when the sunspot rotates with respect to the surrounding region. Rotation introduces a toroidal component of magnetic field, and the associated pressure leads to inflation of the magnetic field pattern. If the differential rotation exceeds about 180 deg, the force-free magnetic field has energy greater than that of an open magnetic-field configuration with the same photospheric boundary conditions. It is concluded that, beyond this point, the force-free field structure is metastable and can be converted into an open field structure by an explosive MHD instability.
Barnes, C. W.↗