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Photoionization of atoms and molecules is one of the fastest processes in nature. The understanding of the ultrafast temporal dynamics of this process often requires the characterization of the different angular momentum channels over a broad energy range. Using a two-photon interferometry technique based on extreme ultraviolet and infrared ultrashort pulses, we measure the phase and amplitude of the individual angular momentum channels as a function of kinetic energy in the outer-shell photoionization of neon. This allows us to unravel the influence of channel interference as well as the effect of the short-range, Coulomb and centrifugal potentials, on the dynamics of the photoionization process.
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http://dx.doi.org/10.1038/s41467-022-32780-5 | DOI Listing |
Nature
September 2025
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA.
Controlling spin currents, that is, the flow of spin angular momentum, in small magnetic devices, is the principal objective of spin electronics, a main contender for future energy-efficient information technologies. A pure spin current has never been measured directly because the associated electric stray fields and/or shifts in the non-equilibrium spin-dependent distribution functions are too small for conventional experimental detection methods optimized for charge transport. Here we report that resonant inelastic X-ray scattering (RIXS) can bridge this gap by measuring the spin current carried by magnons-the quanta of the spin wave excitations of the magnetic order-in the presence of temperature gradients across a magnetic insulator.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2025
Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska-Lincoln, Jorgensen Hall, 855 North 16th Str., NE 68588-0299, Lincoln, Nebraska, 68588-0007, UNITED STATES.
The band structure of ultrathin Pd(111) thin films grown on the CrO(0001) surface was studied by angular-resolved photoemission spectroscopy (ARPES) combined with first-principles calculations. The CrO(0001) interface and the expanded Pd lattice constant appears to significantly affect the occupied band structure of an ultrathin palladium film. A characteristic band splitting is seen in the experimental occupied electronic structure, forming a hexagonal pattern approximately half-way from the Γ" point to the surface Brillouin zone boundary.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Duke University, Thomas Lord Department of Mechanical Engineering and Materials Science, Durham, North Carolina 27708, USA.
Chiral phonons, which are characterized by rotational atomic motion, offer a unique mechanism for transferring angular momentum from phonons to electron spins and other angular momentum carriers. In this Letter, we present a theoretical investigation into the emergence of chiral phonons in a chiral hybrid organic-inorganic perovskite (HOIP) and their critical roles in rigid-body rotation, magnetic moment generation, and spin transport under nonthermal equilibrium conditions. We demonstrate that phonon angular momentum can modify the spin chemical potential via a proposed microscopic Barnett effect, leading to a spatially varying spin chemical potential at the metal/HOIP interface, which subsequently induces spin currents in an adjacent Cu layer, with a magnitude consistent with experimental observations.
View Article and Find Full Text PDFJ Phys Chem A
September 2025
Univ. Rennes, CNRS, IPR (Institut de Physique de Rennes), UMR 6251, Rennes F-35000, France.
We present the first dataset of collisional (de)-excitation rate coefficients of HCN induced by CO, one of the main perturbing gases in cometary atmospheres. The dataset spans the temperature range of 5-50 K. It includes both state-to-state rate coefficients involving the lowest ten and nine rotational levels of HCN and CO, respectively, and the so-called "thermalized" rate coefficients over the rotational population of CO at each kinetic temperature.
View Article and Find Full Text PDFAnn Biomed Eng
September 2025
Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 11, 10115, Berlin, Germany.
The functional interaction of regulatory mechanisms that manage total centre of mass (CoM) energy, frontal plane whole-body angular momentum and mediolateral margin of stability (MoS) during hole negotiation gait was investigated. Joint kinematics, leg posture, total CoM energy, frontal plane whole-body angular momentum, mediolateral MoS and muscle activation patterns of seven bilateral lower leg muscles were assessed in 18 participants. During hole negotiation, we found an increase in the peak-to-peak range of total CoM energy and frontal plane whole-body angular momentum during the preparation, hole and recovery steps, and a decrease in mediolateral MoS at touch-down during the preparation and hole steps compared to level walking, providing evidence of an increased challenge in stability control.
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