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We report an experimental and theoretical study on the shift of the hyperfine splitting frequency of ground-state Li atoms in noble gases, He, Ne, Ar, and Xe. The frequency shift is due to the change in the electron-spin density at the Li nuclei induced by collisions to the noble-gas atoms. The electron density is calculated along the interatomic distance in a pseudopotential and a dispersion potential. Based on the measured and the calculated frequency shifts, we find the importance of attractive force in collisions to helium as well as heavy noble-gas atoms. Taking advantage of the simple energy structure of the Li atom, we obtain the s wave scattering length for free electrons on noble-gas atoms by using the hyperfine splitting frequency as a precise measure.
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http://dx.doi.org/10.1063/5.0085859 | DOI Listing |
J Comput Chem
September 2025
Institute of Atomic and Molecular Physics, Jilin University, Changchun, China.
Quantum chemical calculations have been performed to investigate the structure, stability, and bonding in noble gas (Ng) bound BeB complexes. The present results show that BeB , a charge-separated [Be][B][Be] cluster, can employ both its cationic Be center and anionic B center to bind Ng atoms. It can bind a total of seven Ng atoms, resulting in the formation of a highly symmetric (Ng)Be(Ng)B complex, having D point group.
View Article and Find Full Text PDFPhys Rev Lett
July 2025
Beihang University, The School of Instrumentation and Optoelectronic Engineering, Beijing 100191, China.
We report an ultrasensitive atomic spin sensor employing double spin resonance, achieving a spin signal enhancement of 2600 and a sensitivity of 0.57 fT/sqrt[Hz] under nonzero magnetic field measurements. Furthermore, we establish an in situ alkali-noble-gas spin sensor by tracing the measured spin precession frequency to the nuclear spins gyromagnetic ratio constant with high accuracy.
View Article and Find Full Text PDFAppl Radiat Isot
November 2025
School of Nuclear Science and Technology, University of South China, Hengyang 421001, China; Key Laboratory of Advanced Nuclear Energy Design and Safety, Ministry of Education, Hengyang 421001, China. Electronic address:
The use of Micromegas to construct fission chambers offers advantages of wide range and high sensitivity, providing significant application value in high-intensity thermal neutron measurements, such as reactor neutron flux rate monitoring. However, the pad array readout method of detectors can lead to multiple-triggering from a single signal, which increases the burden on the electronics and limiting the detector's counting capacity. Therefore, it is necessary to optimize the detector structure and operating conditions to restrict the transverse migration and diffusion of charged particles.
View Article and Find Full Text PDFJ Chem Phys
July 2025
Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy.
Ionization processes, promoted by the collisions of CO molecule with noble gas atoms electronically excited in a metastable state, as Ne*, are known as chemi-ionization (CHEMI) reactions. CHEMI reactions of CO have been experimentally investigated in various laboratories exploiting the molecular beam technique, which allowed the resolution of single collision events. The present study, exploiting a proper formulation of optical potential that drives the collision dynamics, provides an internally consistent rationalization of the experimental findings.
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June 2025
Geobiology, University of Göttingen, DE 37073 Göttingen, Niedersachsen, Germany.
Following the evolution of the composition of the atmosphere informs on the entire geological evolution of our planet. The discovery that Archean atmospheric xenon was isotopically fractionated compared to modern atmospheric xenon paved the way for using this noble gas as a tracer of hydrogen escape on the primitive Earth. The curve of the evolution of the isotopic composition of atmospheric xenon remains, however, poorly defined.
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