U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications

NIST Authors in Bold

Displaying 26 - 50 of 2235

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

Superconducting Nanowire Single-Photon Detector Arrays for the Near- to Mid-Infrared

October 31, 2023
Author(s)
Benedikt Hampel, Richard Mirin, Sae Woo Nam, Varun Verma
Superconducting Nanowire Single-Photon Detectors (SNSPDs) are excellent devices for the analysis of faint light from the ultraviolet to the mid-infrared. Recent developments push their broad wavelength bandwidth further into the mid-infrared towards 20 μm

A superconducting nanowire single-photon camera with 400,000 pixels

October 25, 2023
Author(s)
Bakhrom Oripov, Dana Rampini, Jason Allmaras, Matt Shaw, Sae Woo Nam, Boris Korzh, Adam McCaughan
For the past 50 years, superconducting detectors have offered exceptional sensitivity and speed for detecting faint electromagnetic signals in a wide range of applications. These detectors operate at very low temperatures and generate a minimum of excess

Grating magneto-optical traps with complicated level structures

October 25, 2023
Author(s)
Daniel Barker, Peter Elgee, Ananya Sitaram, Eric Norrgard, Nikolai Klimov, Gretchen K. Campbell, Stephen Eckel
We study the forces and optical pumping within grating magneto-optical traps (MOTs) operating on transitions with non-trivial level structure. In contrast to the standard six-beam MOT configuration, rate equation modelling predicts that the asymmetric

Observation of anisotropic superfluid density in an artificial crystal

October 18, 2023
Author(s)
Ian Spielman, Mingshu Zhao, Junhent Tao
We experimentally and theoretically investigate the anisotropic speed of sound of an atomic superfluid (SF) Bose-Einstein condensate in a 1D optical lattice. Because the speed of sound derives from the superfluid density, implying that this density is

Activation loop plasticity and active site coupling in the MAP kinase, ERK2

October 6, 2023
Author(s)
Laurel Pegram, Demian Riccardi, NATALIE AHN
Previous studies of the protein kinase, ERK2, using NMR and hydrogen-exchange measurements have shown changes in dynamics accompanying its activation by phosphorylation. However, knowledge about the conformational motions involved is incomplete. Here, we

Elastic Behavior of Orientation-Correlated Grains in Multiphase Aggregates

October 1, 2023
Author(s)
Thomas Gnaupel-Herold
Diffraction elastic constants (DECs) describe the elastic response of a subset of orientation-correlated grains which share a common lattice vector. DECs reflect the elastic behaviour of the single-crystal constituents through their dependence on grain

Harmonic dependence of thermal magnetic particle imaging

September 22, 2023
Author(s)
Thinh Bui, Mark-Alexander Henn, Weston L. Tew, Megan Catterton, Solomon I. Woods
Advances in instrumentation and tracer materials are still required to enable sensitive and accurate 3D temperature monitoring by magnetic particle imaging. We have developed a magnetic particle imaging instrument to observe temperature variations using

Opportunities for Fundamental Physics Research with Radioactive Molecules

September 18, 2023
Author(s)
Michail Athanasakis-Kaklamanakis, Mia Au, Jochen Ballof, Robert Berger, Anastasia Borschevsky, Alexander Breier, Dmitry Budker, Luke Caldwell, Christopher Charles, Vincenzo Cirigliano, Jordy de Vries, David DeMille, Jacek Jacek Dobaczewski, Ch. E. Dullmann, Ephraim Eliav, Ephraim Eliav, Jonathan Engel, Mingyu Fan, Victor Flambaum, Alyssa Gaiser, Ronald Garcia Ruiz, Konstantin Gaul, Thomas Geisen, Alexander Gottberg, Gerald Gwinner, Reinhard Heinke, Steven Hoekstra, Jason Holt, Nicholas Hutzler, Andrew Jayich, Stephan Malbrunot-Ettenauer, Takayuki Miyagi, Iain Moore, Petr Navratil, Witold Nazarewicz, Gerda Neyens, Eric Norrgard, Nicholas Nusgart, Lukas Pasteka, Roy Ready, Moritz Pascal Reiter, Mikael Reponen, Sebastian Rothe, Marianna Safronova, Andrea Shindler, Jaideep Singh, Leonid Skripnikov, Silviu-Marian Udrescu, Shane Wilkins
Radioactive molecules hold great promise for their discovery potential in diverse fields. The extreme nuclear properties of heavy, short-lived nuclei and the intrinsic sensitivity, flexibility, and quantum control opportunities available to molecules make

Open-path measurement of stable water isotopologues using mid-infrared dual-comb spectroscopy

September 8, 2023
Author(s)
Daniel Herman, Griffin Mead, Fabrizio Giorgetta, Esther Baumann, Nathan Malarich, Brian Washburn, Nathan R. Newbury, Ian Coddington, Kevin Cossel
We present an open-path mid-infrared dual-comb spectrometer (DCS) capable of precise measurement of the stable water isotopologues H216O and HD16O. This system runs in a remote configuration at a rural test site with high uptime and achieves a precision of

Radiative Decay Rate and Branching Fractions of MgF

September 8, 2023
Author(s)
Eric Norrgard, Catherine Cooksey, Stephen Eckel, Nickolas Pilgram, Kayla Rodriguez, Howard W. Yoon, Yuly Andrea Chamorro Mena, Lukas Pasteka, Anastasia Borschevsky
Here we report measured and calculated values of radiative decay rates and vibrational branching fractions for the A$^2\Pi$ state of MgF. The decay rate measurements use time-correlated single photon counting with roughly 1\,\% total uncertainty. Branching

Quantifying the Effect of Guest Binding on Host Environment

August 29, 2023
Author(s)
Angela Stelson, Zack Fishman, Jacob Pawlik, Gosia Musial, Jim Booth, Chris Long, Kathleen Schwarz, Nate Orloff, Hugh Ryan, Angela Grommet, Jonathan Nitschke, Felix Rizzuto
The environment around a host-guest complex is defined by of intermolecular interactions between solvent molecules and counter ions. These interactions govern both the solubility of these complexes and the rates of reactions confined within them11. Such

Broadband Electromagnetic Properties of Engineered Flexible Absorber Materials

August 23, 2023
Author(s)
Luckshitha Suriyasena Liyanage, Connor Smith, Jacob Pawlik, Sarah Evans, Angela Stelson, Chris Long, Nate Orloff, David Arnold, Jim Booth
Flexible and stretchable materials have attracted significant interest for applications in wearable electronics and bioengineering fields. Recent developments also incorporate embedded microwave circuits, components, and systems with engineered flexible
Displaying 26 - 50 of 2235