WorldCat Identities


Works: 7 works in 8 publications in 1 language and 9 library holdings
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High intensity laser propagation in the atmosphere( Book )

2 editions published between 1966 and 1968 in English and held by 2 WorldCat member libraries worldwide

Atmospheric heating by laser pulses in transmission windows has been investigated. Arguments are given for reducing previously given estimates for the absorption in the neighborhood of 10,468 A by nearly one order of magnitude. A study has been initiated of an additional heating mechanism not previously considered, namely collision-induced conversion of laser energy into energy of translational molecular motion. A discussion is given of a classical model and of extensions to a quantum mechanical description. (Author)
Studies of non-radiative energy transfer in aromatic molecules by J. R Novak( Book )

1 edition published in 1969 in English and held by 2 WorldCat member libraries worldwide

An apparatus for automatic recording of T-T absorption spectra has been constructed and used to obtain data for several aromatic hydrocarbons in plastic media or low-temperature glasses. An apparatus for nanosecond flash photolysis and spectroscopy has been devised and built, using a Q-switched ruby laser. The first observations of absorption from the lowest excited singlet states of several aromatic hydrocarbons have been made. The spectral energy level data and lifetime and quantum yield data have been gathered together from a wide variety of sources for several dozen aromatic hydrocarbons. A comprehensive energy level diagram has been constructed for each molecule. Recent theories of radiationless transitions have been reviewed and correlations of their predictions with experimental data have been attempted in a few cases. (Author)
Triplet materials research and eye-protective system( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The second prototype model of a 6 x 8-inch photochromic, windshield segment has been developed, tested and delivered to the Air Force. The device is designed to protect Air Force Pilots against flash blindness resulting from viewing nuclear explosions. The reversible photochromic darkening is based upon the absorption of metastable triplet states of aromatic molecules. These compounds are incorporated into a transparent plate of epoxy plastic. Two plates are attached on the outside of a 6 x 8 x 1 1/2-inch quartz block and the triplet states are excited by uv light from two flash lamps. Black-glass filters absorb the visible light from the flash lamps which would otherwise dazzle the pilot. With a 3000J excitation flash the windshield segment darkens from an open-state absorbance of 0.08 to absorbances of 0.89, 1.68, 2.18 and 2.53, respectively, at times of 50, 100, 150 and 500 microseconds after the start of the flash. The open-state transmission, optical quality and rapidity of buildup of absorbance of the present device are greatly improved compared to the performance of the windshield segment developed on the preceding contract. The windshield segment reopens to half the closed-state absorbance in 1.6 seconds. (Author)
Research on triplet states and photochromism( Book )

1 edition published in 1964 in English and held by 1 WorldCat member library worldwide

The report describes research studies on the photochromic properties of the triplet states of aromatic compounds and their application to the problem of eye-protection against nuclear weapons. Several oxygen-substituted derivatives of the most promising aromatic hydrocarbons investigated to date were obtained and their T-T absorption spectra studied. Two of the four compounds studied appear promising in termsof spectral coverage and photochemical stability. For one compound, naphthocoronene, a extinction coefficient value of 200,000 was obtained. This is an encouragingly high figure and comparable to the value calculated as being necessary to provide protection against flash blindness. Plastic specimens up to 1 inch in diameter and of excellent optical quality can now be made routinely. In a preliminary study of fatigue, a plastic specimen containing chrysene showed no evidence of fatigue after exposure to 50 high-intensity flashes of light

1 edition published in 1965 in English and held by 1 WorldCat member library worldwide

The relativistic quantum theory of the symmetric top implies that the spin J of a particle state can be represented as the sum of four commuting spin operators of lengths given by the positive integers or half-integers n, n', l, l'. If (l + l') is identified with the isospin, 2(n' - n) with the strangeness, and, where applicable, ( -1) to the (n + n') power with the G parity, the simplest choices of n, n', l, l' lead to a correct description of J, I, S, G for every known strongly interacting meson or baryon state. (Author)
Triplet to triplet absorption in organic molecules for use in photochromic devices by J.L Kropp( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The photochromic properties of several substituted aromatics and heterocyclics have been investigated. The absorption spectra, phosphorescence lifetime T-T absorption spectra and the product of triplet extinction coefficient and triplet formation efficiency, were evaluated for representative compounds. Using these data the photochromic properties of heterocyclics are compared to their hydrocarbon analogs. The values of the maximum triplet formation efficiency are lower for heterocyclics than for aromatics. However, broader T-T absorption and more efficient absorption for pumping light suggest that, on balance, heterocyclics are comparable to aromatic hydrocarbons in their effectiveness as photochromic materials. The variation of solvent induces large changes in the photochromic properties of heterocyclics thus providing a useful additional parameter for adjusting their properties. These differences also promise to shed light on the mechanism of radiationless transitions in these compounds. Recommendations for further studies to improve the photochromic properties of heterocyclics are made. (Author)
High intensity laser propagation in the atmosphere. iv. far wing pressure broadening( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The residual absorption in the 10 micrometers window is considered to be due in large measure to the very far wings of the pure-rotational lines of H2O. Experimental data indicate the broadening is mainly self-broadening arising from binary collision between H2O molecules. In order to explain the relatively large absorption observed at 10 micrometers, studies were carried out based upon a model of hindered rotational motion (libration) in which the ordinary rotational motion is suppressed by the strong dipole-dipole force during close collisions. Present results give a cross section which is one-half the experimental value multiplied by a Boltzmann factor describing the probability of achieving a frequency-matching configuration. It was found that for the particular model studied that this factor is too small. However, our studies indicate a variety of possible modifications which are capable of obtaining agreement with experiment. (Author)
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