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Search Publications by: James S. Sims (Assoc)

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Displaying 1 - 25 of 30

Exponentially correlated Hylleraas-Configuration Interaction studies of atomic systems. III Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance singlet S to singlet P Transition

July 22, 2023
Author(s)
James S. Sims, Bholanath Padhy, Maria Ruiz
A generalization of the Hylleraas-Configuration Interaction method (Hy-CI) first proposed by Wang et al., the Exponentially Correlated Hylleraas-Configuration Interaction method (E-Hy-CI) in which the single rij of an Hy-CI wave function is generalized to

High-Precision Hy-CI and E-Hy-CI studies of Atomic and Molecular Properties

September 29, 2021
Author(s)
James S. Sims, Maria Ruiz, Bholanath Padhy
This review presents a survey of the most important achievements in atomic and molecular calculations obtained with the Hylleraas-configuration interaction method (Hy-CI) and its extension the exponentially correlated Hylleraas-configuration interaction

Parallel Generalized Real Symmetric-Definite Eigenvalue Problem

November 6, 2020
Author(s)
James S. Sims, Maria B. Ruiz
A computationally fast Fortran 90+ quadruple precision portable parallel GRS- DEP (generalized real symmetric-definite eigenvalue problem) package suitable for large (80,000 x 80,000 or greater) dense matrices is discussed in this paper.

Application Creation for an Immersive Virtual Measurement and Analysis Laboratory

December 21, 2016
Author(s)
Wesley N. Griffin, William L. George, Terence J. Griffin, John G. Hagedorn, Thomas M. Olano, Steven G. Satterfield, James S. Sims, Judith E. Terrill
Content creation for realtime interactive systems is a difficult problem. In game development, content creation pipelines are a major portion of the code base and content creation is a major portion of the budget. In research environments, the choice of

Mechanism for controlling the exciton fine structure in quantum dots using electric fields: Manipulation of exciton orientation and exchange splitting at the atomic scale

October 7, 2013
Author(s)
Garnett W. Bryant, Natalia Malkova, James S. Sims
We use atomistic tight-binding theory with a configuration interaction description of Coulomb and exchange effects to describe excitons in quantum dots in a vertical electric field. We show that field-induced manipulation of exciton orientation and phase

Extending Measurement Science to Interactive Visualization Environments

January 30, 2009
Author(s)
Judith E. Terrill, William L. George, Terence J. Griffin, John G. Hagedorn, John T. Kelso, Thomas M. Olano, Adele P. Peskin, Steven G. Satterfield, James S. Sims, Jeffrey W. Bullard, Joy P. Dunkers, Nicos Martys, Agnes A. O'Gallagher, Gillian Haemer
We describe a method for creating a visual laboratory to interactively measure and analyze scientific data. We move the normal activities that scientists perform to understand their data into the visualization environment. The visualization environment is

Accelerating Scientific Discovery through Computation and Visualization III. Tight-binding Wave Functions for Quantum Dots

June 2, 2008
Author(s)
James S. Sims, John G. Hagedorn, Steven G. Satterfield, Terence J. Griffin, William L. George, Howard Hung, John T. Kelso, Thomas M. Olano, Adele P. Peskin, Judith E. Terrill, Garnett W. Bryant, Jose G. Diaz
This is the third in a series of articles that describe, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing, visualization, and machine learning to accelerate scientific

Intrinsic Surface States in Semiconductor Nanocrystals: HgS Quantum Dots

March 23, 2005
Author(s)
James S. Sims, Garnett W. Bryant, Howard Hung
Confined states in typical nanocrystals are localized to the dot interior. Surface states are extrinsic states localized at unsaturated dangling bonds or surface defects. We show that intrinsic surface states occur in nanocrystals made from negative gap