Physical Sciences and Mathematics Commons^™

Semiclassical Theory Of Inelastic Collisions Ii. Momentum Space Formulation, John B. Delos, Walter R. Thorson

Arts & Sciences Articles

The time-dependent equations of the classical picture of inelastic collisions (classical-trajectory equations) are derived using the momentum-space semiclassical approximation. Thereby it is shown that the classical-trajectory equations remain valid in the vicinity of classical turning points provided that (a) the momentum-space semiclassical approximation is valid, (b) the trajectories for elastic scattering in the various internal states differ only slightly, and (c) the slopes of the elastic scattering potentials have the same sign. A brief review of the existing derivations of the classical-trajectory equations is given, and the general conditions for their validity are discussed.

Physical And Geological Studies Of The Proposed Bridge-Tunnel Crossing Of Hampton Roads Near Craney Island, C. S. Fang, B. J. Neilson, A. Y. Kuo, R. J. Byrne, C. S. Welch

Reports

Part 1: James River Hydraulic Model Tests

Part 2: Impact on Shoreline, Hampton Flats and Newport News Point Area

Part 3: Drogue Study, Hampton Flats and Newport News Point

Part 4: Hydraulic Model Test Results

Studies Of The Potential Curve Crossing Problem Ii. General Theory And A Model For Close Crossings, John B. Delos, W. R. Thorson

Arts & Sciences Articles

A unified formal treatment of the two-state potential-curve-crossing problem in atomic collision theory is presented, and the case of close crossings analyzed in detail. A complete solution for this case, including necessary computations, is given using a suitable generalization of the linear model originally suggested by Landau, Zener, and Stueckelberg. Our solution is based upon a hierarchy of approximations concerned with (i) choice of a discrete basis set for electronic coordinates, (ii) semiclassical treatment of the nuclear motion, (iii) an appropriate model for the two-state electronic Hamiltonian, and (iv) a complete solution to that model.

Semiclassical Theory Of Inelastic Collisions I. Classical Picture And Semiclassical, John B. Delos, W. R. Thorson, Stephen Knudson

Arts & Sciences Articles

This series of papers is concerned with the derivation of the equations of the classical picture of atomic collisions, iℏddtdi(t)=Σjhij(t)dj(t), which describe the "time" dependence of electronic-quantum-state amplitudes as the nuclei move along a classical trajectory. These equations are derived in two ways. In the first formulation, which coincides with the intuitive classical picture of the collision, the nuclear part of the wave function is treated as a superposition of narrow wave packets, each traveling along a classical trajectory. In the second formulation, a semiclassical approach is used. The validity and meaning of the two formulations are discussed and compared.

Oceanographic Data Collected In The Chesapeake Bight Of The Virginian Sea From 1966 Though 1969, E. P. Ruzecki, J. J. Norcross, F. J. Wojcik

Reports

This report is intended to make unsynthesized oceanographic data readily available to the scientific community. 3 Similar reports are envisioned which will include physical, chemical, biological and geological data collected by personnel of the Virginia Institute ·of Marine Science in areas of the continental shelf, and coastal zone to include beaches, wetlands, estuaries and tidal rivers - areas in which the Commonwealth of Virginia has a vested interest.

Instructions For Using Oceanography Form 1 (Virginia Institute Of Marine Science Hydrographic Data Form), Richard W. Moncure

Reports

Instructions for coding oceanographic data on Form 1.

Solutions Of The Two-State Potential-Curve-Crossing Problem, John B. Delos, W. R. Thorson

Arts & Sciences Articles

A general theory of the two-state curve-crossing problem has been developed, with a complete solution of an accurate model for "close" crossings (including numerical computations for strong coupling). Results clarify the position of the Landau-Zener approximation and its improvements by Nikitin and others, provide a general way of extending these approximations into regions often treated incorrectly (including the high-energy limit), and can be readily adapted to simple, rapid calculations.

Data Report: Operation York River, 1969, P. V. Hyer, E. P. Ruzecki, C. S. Fang

Reports

A field survey was carried out in October 1969 to gather field data from the Mattaponi, Pamunkey and York rivers in order to construct mathematical models for salinity and dissolved oxygen. The results of the field operation are presented, together with a description of the methods and instruments used in the data collection and analysis.

Study Of Channel Sediments, Baltimore Harbor, Norfolk Harbor, York Entrance Channel, R. J. Huggett

Reports

3ot~om sediment samples were collected from seven channel locations in the Chesapeake Bay and communicating river systems. The sampling format involved. long cores (designated "L") taken at two nautical mile intervals and surface samples (designated "S) taken at one-half mile intervals.

Groundwater Flow In A Sandy Tidal Beach 2. Two-Dimensional Finite Element Analysis., C. S. Fang, S. N. Wang, W. Harrison

VIMS Articles

Two-dimensional finite element techniques are described that model closely the complicated fluctuations osbserved in the water table of an ocean beach. The use of triangular elements permits the specification of more realistic boundary conditions than the use of line elements in a one-dimensional model. Also, results obtained from the two-dimensional model for the region closet o the ocean compare more favorably with field data than results obtained from the one-dimensional finite element model.

Heavy Metals - An Inventory Of Existing Conditions, M. E. Bender, R. J. Huggett, H. D. Slone

VIMS Articles

In this paper we report on studies undertaken to: (1) establish 1nercury levels in biota and sediments from the lower portion of Chesapeake Bay; (2) describe the pattern of metal distribution in oysters from 3 Virginia estuaries; and (3) determine if estuarine sediments can be used to detect the effects of man's activities on the environn1e nt. To date, mercury analyses of biota from the Bay area have sho\vn no levels in excess of FDA guidelines, nor have they indicated any influence of man's activities in the areas studies. Oysters have been shown to vary naturally in their body burdens …

Bahamas Bibliography : A List Of Citations For Scientific, Engineering And Historical Articles Pertaining To The Bahama Islands, Carol Fang, W. Harrison

Reports

Specialized bibliographies are sometimes needed in connection with the research studies being pursued at the Virginia Institute of Marine Science. The Bahamas Bibliography arose out of the needs of marine geologists, biologists and physical oceanographers engaged in studies of beaches, fishes and inlet currents in the Bahama Islands. Although the present bibliography may suffer from completeness, it significantly surpasses in number of citations the only other known bibliography of like kind.

Inner Shelf Sediments Off Chesapeake Bay. I - General Lithology And Composition, Maynard M. Nichols

Reports

The sedimentary materials and bottom topography of more than 2400 square miles of the inner continental shelf floor north off the Chesapeake Bay entrance have been surveyed for potential mineral resources. Sediments consist of two principal types: (1) fine sand and (2) medium to coarse sand. The fine sand is grey-colored, subrounded, rich in quartz and relatively 11clean 11 and well sorted. The medium-coarse sand is typically iron-stained, rich in shell and poorly sorted. The fine sand covers inner parts of the shelf floor whereas medium to coarse sand covers seaward parts. Additionally, shell-rich medium to coarse sand occurs on …

Chesapeake Bay Bibliography - Volume Ii Virginia Waters, Pamela S. Tennyson, Susan O. Barrick, Frank J. Wojcik, William J. Hargis Jr.

Reports

The Chesapeake Bay Bibliography was initiated by the Virginia Institute of Marine Science in response to growing resource management problems of the Chesapeake Bay and its tributaries. With these problems carne the realization that planning and management of such a great natural resource is an overwhelming task requiring the best available information. This bibliography, therefore, was undertaken to document existing sources of information, to help identify research and data gathering needs, and to develop a comprehensive research and information services programs for individuals interested in research on, and management of the natural resources of the Chesapeake Bay region.

This, the …