Electrical and Computer Engineering Commons^™

Discrete And Diffuse Emission Following Two-Photon Excitation Of The E State In Molecular Iodine, D. L. Rousseau, P. F. Williams

P. F. (Paul Frazer) Williams Publications

We studied the fluorescence spectrum of E →B transitions in molecular iodine following two-photon absorption. Discrete re-emission lines terminating in B-state levels ranging from ν = 0 to the dissociation limit were observed in addition to a series of broad diffuse lines. These diffuse lines represent the first observation of Condon "internal diffraction” resulting from a single vibronic state, and therefore the variation of the bands directly displays the variation of the Franck-Condon factor.

Self-Consistent Dielectric Response Of A Quasi-One-Dimensional Metal At High Frequencies, P. F. Williams, Aaron N. Bloch

P. F. (Paul Frazer) Williams Publications

We present the results of a calculation of the frequency- and wave-vector-dependent longitudinal dielectric function of a quasi-one-dimensional electron gas. The electrons are taken to be localized to the chains and both the tight-binding and free-electron extremes are considered along the chain axis. Local-field effects are included. Dispersion curves for plasmons and single-particle-excitation spectra are presented. We find that the plasmon modes are not Landau damped and that for long wavelengths these modes have eigenfrequencies ranging continuously from the usual three-dimensional plasma frequency for propagation along the chain axis to zero for propagation perpendicular to it. Finally, we discuss the …

Optical Excitation Of Plasmons In A Quasi-One-Dimensional Conductor, P. F. Williams, M. A. Butler, D. L. Rousseau

P. F. (Paul Frazer) Williams Publications

We have carefully determined the optical spectrum of K₂Pt(CN) ₄Br_0.3 - 3H₂O near the reflectivity edge. Our data reveal, in addition to the expected monotonic background, a broad peak in ε₂ (ω) above a threshold coinciding with the zero of ε₁ (ω) near 16000 cm^-1. We assign this band to indirect excitation of plasmons. Details of the excitation of plasmons are discussed with particular attention being paid to the problems presented by the one-dimensional character of the material. It is concluded that the electronic structure of this material cannot be …

Resonance Fluorescence And Resonance Raman Scattering: Lifetimes In Molecular Iodine, P. F. Williams, D. L. Rousseau, D. H. Dworetsky

P. F. (Paul Frazer) Williams Publications

We report a significantly shortened scattering lifetime in molecular iodine when the frequency of a single-mode 5145-Å incident laser is tuned away from resonance with a discrete transition. This observation of a shortened scattering time is indicative of what has been conventionally called a Raman process. Off-resonance lifetime measurements, as reported here, may provide a means of determining the relative contribution to the absorption line-width of homogeneous and inhomogeneous broadening.

Hall Effect Magnetometer, John A. Woollam, Harry A. Beale, Ian L. Spain

Department of Electrical and Computer Engineering: Faculty Publications

A magnetometer utilizing a single crystal of Bi²Se³ having a rhombohedral crystal structure is described along with a method for making such a device. The Bi²Se³ has a positive or negative Hall coefficient and a carrier concentration of about 10¹⁸to10²⁰ per cubic centimeter.

Symmetry-Forbidden Resonant Raman Scattering In Cu2O, S. P. S. Porto, P. F. Williams

P. F. (Paul Frazer) Williams Publications

We have observed resonant Raman scattering from the two longitudinal branches of the Raman-forbidden F_{1u modes of Cu2O. The agreement between our measured scattering cross section as a function of excitation frequency and a calculated cross section which assumes an intraband Frohlich electron-phonon interaction is good. This represents a quantitative confirmation of the resonant-Raman-scattering theory proposed by Martin.}

Resonant Raman Scattering From Iodine: Spectral Changes With Excitation Frequency, P. F. Williams, D. L. Rousseau

P. F. (Paul Frazer) Williams Publications

We have recorded high-resolution resonant Raman spectra of molecular iodine which show very pronounced systematic spectral band-shape variations with incident laser frequency. This frequency dependence and the presence of the multiple overtones in resonant Raman scattering from iodine may be explained by a theory in which the scattering intensity depends on Franck-Condon overlap integrals. We have obtained semiquantitative agreement between the observed spectra and spectra calculated from this theory.

Digital Video Display System Using Cathode-Ray Tube, George M. Low, Arthur I. Zygielbaum, Warren L. Martin, Alexander Engel

School of Natural Resources: Faculty Publications

A digital video display system (DWDS) is disclosed for display of image, alphanumeric and other data on a cathode-ray tube (CRT) with sequential raster scan and two, four or eight gray shades. The DVDS includes a central processing unit for ac tivating the system, selecting the X (horizontal axis) and Z (in tensity modulation) modes, and designating the starting loca tion of two successive rasters of data from a memory accessed by a data multiplexer subsystem (DMS). At the end of each raster, the DMS interrupts the computer for a new starting lo cation of a raster of data to …

Association Of College And University Telecommunications Administrators Presidents

ACUTA: Other Publications

ELWYN HULL

1980-1981

CONSTANCE GENTRY

1981-1982

L. STEVE HARWARD

1982-1983

MICHAEL A. TONER

1983-1984

RUTH A. MICHALECKI

1984-1985

JOHN W. SLEASMAN

1985-1986

MALCOLM READER

1978-1980

ELWYN HULL

1980-1981

CONSTANCE GENTRY

1981-1982

L. STEVE HARWARD

1982-1983

MICHAEL A. TONER

1983-1984

RUTH A. MICHALECKI

1984-1985

JOHN W. SLEASMAN

1985-1986

The Pennsylvania State University

ACUTA: Other Publications

Attached is a draft of the charter membership 'letter we discussed at the meeting in Chicago last week. PLEASE. I have no special "pride of authorship" in this type of thing, so I implore you to be ruthless in your criticism, additions, deletions, etc. We want to entice a good membership drive, not put laurels on my head. So, if you'll go over this, make comments and return to me just as soon as possible, I compile the comments, prepare the final copy and have it printed.

Raman Scattering From Localized Vibrational Modes In Gap, D. T. Hon, W. L. Faust, W. G. Spitzer, P. F. Williams

P. F. (Paul Frazer) Williams Publications

High-frequency localized vibrational modes of impurities in a III-V compound have been observed by Raman scattering. Three lines from the GaP samples closely correspond to some loccal modes previously reported in infrared studies, and depolarization measurements tend to confirm their proposed assignments. We describe several attractive features of this method for the study of semiconductor impurities.

A Noise Figure Lower Bound And A Frequency Converter, Grant Myers

Department of Electrical and Computer Engineering: Faculty Publications

This article establishes a lower bound for the noise figure of two networks in cascade. This is illustrated by means of a passive low-level frequency converter which utilizes a back diode as a nonlinear conductance. Other investigators have analyzed the properties of low-level frequency converters. However, the greatest lower bound of a combination of the converter and intermediate frequency amplifier system was not considered previously and is the subject of this paper. Knowledge of this lower bound has practical significance because if a measured value of noise figure is less than this lower bound, it follows that the measurement is …

The Magnetocardiogram A New Approach To The Fields Surrounding The Heart, R. A. Stratbucker, C. M. Hyde, S. E. Wixon

Department of Electrical and Computer Engineering: Faculty Publications

Experiments have been conducted which reveal the existence of a detectable magnetic field associated with cardiac electrical activity. The relationship between the magnetic record and the electrocardiogram has been explored and it is shown that under certain conditions of axis orientation the voltage induced into a toroidal sensing element around the heart has the form of the first time derivative of the electrocardiogram. A formula based on Maxwell's equations has been developed to relate these two phenomona.

An Experimental Study Of The Cathode Fall In Helium And Argon With Wire Cathodes, L. G. Raub

University Studies (University of Nebraska) (1888–1984)

It was recognized rather early in the study of the phenomena of discharge of electricity through gases that the ordinary laws of conduction as found in solid and liquid conductors are not applicable to gases. It was shown by Zeleny and independently by Child that Ohm's law by no means represents the distribution of potential between electrodes in an ionized gas, but that the potential gradient is large in the vicinity of the electrodes, and not uniform throughout the space between them. When the pressure of the gas surrounding the electrodes is reduced to one or two millimeters and a …

Comparative Observations On The Evolution Of Gas From The Cathode In Helium And Argon, Clarence A. Skinner

University Studies (University of Nebraska) (1888–1984)

No abstract provided.