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1994

Faculty Publications, Department of Physics and Astronomy

Articles 1 - 5 of 5

Full-Text Articles in Physics

Small Polarons And The Electronic Properties Of Mo2S3, Adilgiry A. Kusov, Roger D. Kirby Dec 1994

Small Polarons And The Electronic Properties Of Mo2S3, Adilgiry A. Kusov, Roger D. Kirby

Faculty Publications, Department of Physics and Astronomy

We investigate the small-polaron mechanism as a possible explanation of electrical-conduction and electrical-noise properties of the linear chain material Mo2S3. Experimental conductivity and noise data obtained in earlier papers [Phys. Rev. B 38, 3973 (1988); Phys. Rev. B 39, 5139 (1989)] are analyzed in terms of a small-polaron mechanism and double-well potential model. We interpret the observed electronic properties in terms of kinetic equations describing the interaction of free carriers with fluctuations of density of the lattice. Appropriate kinetics equations to describe this interaction, which leads to small-polaron formation, are derived. These equations are found to explain ...


Magnetization Reversal In Nanoscale Magnetic Films With Perpendicular Anistropy, Roger D. Kirby, J.X. Shen, Robert J. Hardy, David J. Sellmyer Apr 1994

Magnetization Reversal In Nanoscale Magnetic Films With Perpendicular Anistropy, Roger D. Kirby, J.X. Shen, Robert J. Hardy, David J. Sellmyer

Faculty Publications, Department of Physics and Astronomy

We present experimental results on magnetization reversal for a class of nanoscale magnetic films with perpendicular magnetic anistropy and develop a model that describes a variety of related experiments. In this model the sample is divided into identical single domain cells that interact through dipolar fields and a nearest-neighbor domain-wall interaction. Monte Carlo simulations give insights into the relationship between macroscopic magnetic parameters and the reversal behavior and demonstrate the important role that thermal activation plays in the reversal process.


Slowing Of 85Rb Atoms With Isotropic Light, Herman Batelaan, S. Padua, D. H. Yang, C. Xie, R. Gupta, Harold Metcalf Mar 1994

Slowing Of 85Rb Atoms With Isotropic Light, Herman Batelaan, S. Padua, D. H. Yang, C. Xie, R. Gupta, Harold Metcalf

Faculty Publications, Department of Physics and Astronomy

We have demonstrated the slowing of a rubidium atomic beam by isotropic monochromatic light. The results agree with a model calculation, thus allowing its use for designing a practical isotropic light slower. The large hyperfine splittings of rubidium lead to natural multifrequency slowing, which is also included in our model.


Simplest Atomic System For Sub-Doppler Laser Cooling, R. Gupta, S. Padua, C. Xie, Herman Batelaan, Harold Metcalf Jan 1994

Simplest Atomic System For Sub-Doppler Laser Cooling, R. Gupta, S. Padua, C. Xie, Herman Batelaan, Harold Metcalf

Faculty Publications, Department of Physics and Astronomy

Sub-Doppler laser cooling requires optical pumping among differently light-shifted ground-state sublevels. We describe a study of the simplest possible angular-momentum configuration that permits all sub-Doppler cooling phenomena. The Jg = 1 ⟹ Je = 0 angular-momentum configuration shows recoil-limited cooling in the two most well-known types of polarization gradient, magnetically induced laser cooling, velocity-selective resonances, transient cooling, and velocity-selective population trapping.


Steps Toward Determinaton Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. V. Variability Of The Ultraviolet Continuum And Emission Lines Of Ngc 3783, G. A. Reichert, P. M. Rodriguez-Pascual, D. Alloin, J. Clavel, D. Michael Crenshaw, Gerard A. Kriss, Julian Henry Krolik, Matthew A. Malkan, Hagai Netzer, Bradley M. Peterson, W. Wamsteker, A. Altamore, B. Altieri, K. S.J. Anderson, J. H. Blackwell Jr,, C. Boisson, N. Brosch, T. E. Carone, M. Dietrich, M. N. England, I. N. Evans, A. V. Filippenko, C. Martin Gaskell, M. Goad, P. M. Gondhalekar., K. Horne, D. Kazanas, W. Kol Latschny, A. P. Koratkar, Kirk T. Koristag, G. M. Macalpine, D. Maoz, T. Mazeh, B. Mccollum, H. Richard Miller, C. Mendes De Oliveira, Paul T. O'Brien, M. G. Pastoriza, D. Pelat, E. Perez, G. C. Perola, Richard William Pogge, R. L. Ptak, M. C. Recondo-Gonzalez, J. Rodriguez-Espinosa, E. I. Rosenblatt, A. C. Sadun, M . Santos-Lleo, J. C. Shields, C. R. Shrader, J. M. Shull, S. M. Simkin, M. L. Sitko, M. A.J Snuders, L. S. Sparke, G. M. Stirpe, R. Stoner, T. . Storchi-Bergm, W. H. Sun, T. F. Wang, W. F. Welsh, R. J. White, C. Winge, W. Zhen Jan 1994

Steps Toward Determinaton Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. V. Variability Of The Ultraviolet Continuum And Emission Lines Of Ngc 3783, G. A. Reichert, P. M. Rodriguez-Pascual, D. Alloin, J. Clavel, D. Michael Crenshaw, Gerard A. Kriss, Julian Henry Krolik, Matthew A. Malkan, Hagai Netzer, Bradley M. Peterson, W. Wamsteker, A. Altamore, B. Altieri, K. S.J. Anderson, J. H. Blackwell Jr,, C. Boisson, N. Brosch, T. E. Carone, M. Dietrich, M. N. England, I. N. Evans, A. V. Filippenko, C. Martin Gaskell, M. Goad, P. M. Gondhalekar., K. Horne, D. Kazanas, W. Kol Latschny, A. P. Koratkar, Kirk T. Koristag, G. M. Macalpine, D. Maoz, T. Mazeh, B. Mccollum, H. Richard Miller, C. Mendes De Oliveira, Paul T. O'Brien, M. G. Pastoriza, D. Pelat, E. Perez, G. C. Perola, Richard William Pogge, R. L. Ptak, M. C. Recondo-Gonzalez, J. Rodriguez-Espinosa, E. I. Rosenblatt, A. C. Sadun, M . Santos-Lleo, J. C. Shields, C. R. Shrader, J. M. Shull, S. M. Simkin, M. L. Sitko, M. A.J Snuders, L. S. Sparke, G. M. Stirpe, R. Stoner, T. . Storchi-Bergm, W. H. Sun, T. F. Wang, W. F. Welsh, R. J. White, C. Winge, W. Zhen

Faculty Publications, Department of Physics and Astronomy

We report on the results of intensive ultraviolet spectral monitoring of the Seyfert 1 galaxy NGC 3783. The nucleus of NGC 3783 was observed with the International Ultraviolet Explorer satellite on a regular basis for a total of 7 months, once every 4 days for the first 172 days and once every other day for the final 50 days. Significant variability was observed in both continuum and emission-line fluxes. The light curves for the continuum fluxes exhibited two well-defined local minima or "dips," the first lasting ≤20 days and the second ≤ 4 days, with additional episodes of relatively rapid flickering ...