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A Gurtu P K Malhotra I S Mittra P M Sood SC Gupta VK Gupta GL Kaul LK Mangotra Y Prakash NK Rao ML Sharma 《Pramana》1974,3(5):311-322
This is a continuation of our earlier investigation (Gurtuet al 1974Phys. Lett. 50 B 391) on multiparticle production in proton-nucleus collisions based on an exposure of emulsion stack to 200 GeV/c beam at the NAL. It is found that the ratioR em = 〈n s〉/〈n ch〉, where 〈n ch〉 is the charged particle multiplicity in pp-collisions, increases slowly from about 1 at 10 GeV/c to 1·6 at 68 GeV/c and attains a constant value of 1·71 ± 0·04 in the region 200 to 8000 GeV/c. Furthermore,R em = 1·71 implies an effectiveA-dependence ofR A =A 0.18,i.e., a very weak dependence. Predictions ofR em on various models are discussed and compared with the emulsion data. Data seem to favour models of hadron-nucleon collisions in which production of particles takes place through adouble step mechanism,e.g., diffractive excitation, hydrodynamical and energy flux cascade as opposed to models which envisage instantaneous production. 相似文献
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The noise characteristic of available laser sources limits the sensitivity of many types of nonlinear spectroscopy. We show
how to maximize the sensitivity by optimizing the strength of a local oscillator wave in a heterodyne detection scheme without
altering the amplitude of the wave being detected. The intensity profile of the optimum local oscillator closely matches that
of the incident probe wave, but the optimum intensity is much less than that of the probe under realistic conditions. A general
signal-to-noise analysis applicable to all nonlinear spectroscopy techniques is presented along with specific applications
to coherent Raman spectroscopy, two-photon absorption, saturation spectroscopy, and optical coherent transient techniques.
A simple optimization procedure employing polarization selection rules is described. Detailed calculations are performed for
the case of TEM00 waves interacting via a third-order nonlinear susceptibility and for the case where the sample is simultaneously probed at
many different frequency combinations.
Supported by the National Science Foundation and Office of Naval Research. 相似文献
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The effects of substituent type and position on the proton transfer reaction of 3-hydroxytropolone(3-OHTRN) have been investigated theoretically by using density functional theory at the level of B3LYP/ 6-31+G** method. The influence of solvent on the proton transfer reactions of substituted 3-OHTRN has been examined using the self-consistent isodensity polarized continuum model(SCI-PCM) in water. As a result, while the proton transfer reaction is kinetically the easiest by substitution on position 3 of-NH2 group in the gas phase, it is kinetically the easiest by substitution on position 5 of the same group in water. In addition, these reactions are either kinetically or thermodynamically easier in the gas phase than that in water, except the reaction of structure with-NH2 group at position 6. 相似文献
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G.L. Eesley 《Journal of Electron Spectroscopy and Related Phenomena》1983,30(1):25-34
We present the first experimental results which demonstrate a quadratic relationship between the enhanced Raman scattering from molecules on Ag surfaces and roughness-coupled surface-plasmon radiation. These results are interpreted by a model which includes both roughness assisted surface-plasmon scattering and radiative coupling. 相似文献