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Displaying 1 - 25 of 41

Developing Interoperable, Accessible Software via the Atomic, Molecular, and Optical Sciences Gateway: A Case Study of the B-spline atomic R-Matrix code Graphical User Interface

October 3, 2024
Author(s)
Barry I. Schneider, kathryn hamilton, Sudhakar Pamidighantam, Tom Wolcott
The Atomic, Molecular, and Optical Science Gateway\citeamosgateway} is a comprehensive cyber\-infrastructure for research and educational activities in computational AMO science. The \hbox$B$-Spline} atomic \hbox$R$-Matrix} (BSR) suite of programs is

Two-electron interference in two-photon attosecond double ionization of neon

July 2, 2024
Author(s)
Siddhartha Chattopadhyay, Carlos Marante, Barry I. Schneider, C. William McCurdy, Luca Argenti
The pump-probe experiments enabled by X-ray free-electron lasers (XFEL) will allow us to directly observe correlated electronic motion with attosecond time resolution by detecting photoelectron pairs in coincidence. In helium, the transition between the

ASTRA: a Transition-Density-Matrix Approach to Molecular Ionization

November 3, 2023
Author(s)
Luca Argenti, Juan Martin Randazzo, carlos maranthe, Jeppe Olsen, Siddhartha Chattopadhyay, Barry I. Schneider
We describe ASTRA (AttoSecond TRAnsitions), a new close-coupling approach to molecular ionization that uses many-body transition density matrices between ionic states with arbitrary spin and symmetry, in combination with hybrid integrals between Gaussian

Simulation For All: The Atomic, Molecular, and Optical Science Gateway

June 1, 2023
Author(s)
kathryn hamilton, klaus bartschat, nicolas douguet, sudhakar pamidighantam, robert lucchese, Barry I. Schneider
A challenge facing the Atomic, \hboxMolecular}, and Optical Science (AMOS) community is the lack of a coordinated approach to using and sharing the computational tools and data that have grown organically in the theoretical community. The Atomic, Molecular

Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues: IV. Vibrationally-resolved ionization of the ground and excited electronic states.

January 31, 2023
Author(s)
Yuri Ralchenko, Barry I. Schneider, Liam Scarlett, Eric Jong, Igor Bray, Starsha Odelia, Mark Zammit, Dmitry Fursa
We present a comprehensive set of vibrationally-resolved cross sections for electron-impact ionization of molecular hydrogen and its isotopologues (H2, D2, T2, HD, HT, and DT) in both the ground and excited electronic states. We apply the adiabatic-nuclei

Convergent close-coupling calculations of electron scattering on HeH+

October 31, 2022
Author(s)
Barry I. Schneider
We use the molecular convergent close-coupling (MCCC) method to perform calculations of 10–1000 eV electron scattering on the ground state of HeH+. Cross sections are presented for excitation of the n = 2−3 singlet and triplet states (where n is the united

Graph Convolutional Neural Network Applied to the Prediction of Normal Boiling Point

February 4, 2022
Author(s)
Chen Qu, Anthony J. Kearsley, Barry I. Schneider, Walid Keyrouz, Thomas C. Allison
In this article, we describe training and validation of a machine learning model for the prediction of organic compound normal boiling points. Data are drawn from the experimental literature as captured in the NIST Thermodynamics Research Center (TRC)

A Two-Channel R-Matrix Analysis of Magnetic Field Induced Feshbach Resonances

October 12, 2021
Author(s)
N Nygaard, Barry I. Schneider, Paul S. Julienne
A Feshbach resonance arises in cold atom scattering due to the complex interplay between several coupled channels. However, the essential physics of the resonance may be encapsulated in a simplified model consisting of just two coupled channels. In this

A Multi-Center Quadrature Scheme for the Molecular Continuum

June 1, 2021
Author(s)
Barry I. Schneider, Heman Gharibnejad, nicholas douguet, Luca Argenti, Jeppe Olsen
A common way to evaluate electronic integrals for polyatomic molecules is to use Becke's partitioning scheme [\colorblue}J. Chem. Phys. \bf 88}, 2547 (1988)}] in conjunction with multi- center grids of comparable size. Becke's scheme, however, is efficient

A Science Gateway for Atomic and Molecular Physics

January 7, 2020
Author(s)
Barry I. Schneider, Klaus Bartschat, Oleg Zatsarinny, Igor Bray, Fernando Martin, Armin Scrinzi, Sudhakar Pamidighantam, Jonathan Tennyson, Jimena Gorfinkiel, Markus Klinker
We describe the creation of a new Atomic and Molecular Physics science gateway (AMPGateway). The gateway is designed to bring together a subset of the AMP community to work collectively to make their codes available and easier to use by the partners as

Numerical methods every atomic and molecular theorist should know

December 16, 2019
Author(s)
Barry I. Schneider, Heman Gharibnejad
This review article discusses a few theoretical and numerical approaches that have been successfully used to treat electron scattering and photoionization of atoms and molecules and the interaction of those systems with intense, short-pulse electromagnetic