We perform the four-body calculation of the hyperfine structure in the first rotational state J=1 of the H_{2}, D_{2}, and HD molecules and determine the accurate value for the deuteron electric quadrupole moment Q_{d}=0.285 699(15)(18) fm^{2} in significant disagreement with former spectroscopic determinations. Our results for the hyperfine parameters agree very well with the currently most accurate molecular-beam magnetic resonance measurement performed several decades ago by N.F. Ramsey and coworkers. They also indicate the significance of previously neglected nonadiabatic effects. Moreover, a very good agreement with the recent calculation of Q_{d} based on the chiral effective field theory, although much less accurate, indicates the importance of the spin dependence of nucleon interactions in the accurate description of nuclei.
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http://dx.doi.org/10.1103/PhysRevLett.125.253001 | DOI Listing |
J Am Chem Soc
January 2025
Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
The delocalization length of charge carriers in organic semiconductors influences their mobility and is an important factor in the design of functional materials. Here, we have studied the radical anions of a series of linear and cyclic butadiyne-linked porphyrin oligomers using CW-EPR, H Mims ENDOR and NIR/MIR spectroelectrochemistry together with DFT calculations and multiscale molecular modeling. Low-temperature hyperfine EPR spectroscopy and optical data show that polarons are delocalized nonuniformly over about four porphyrins with most of the spin density on just two units even in the cyclic structures, in which all porphyrin sites are identical.
View Article and Find Full Text PDFSci Rep
January 2025
Centre for Molecular and Materials Science, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada.
This paper describes muon spin spectroscopy studies of 12-phosphatetraphene stabilized by a peri-trifluoromethyl group and a meso-aryl substituent. Even though the prepared solution in tetrahydrofuran (THF) was quite dilute (0.060 M) for transverse-field muon spin rotation (TF-µSR) measurements, the π-extended heavier congener of tetraphene presented a pair of signals due to a muoniated radical from which the muon hyperfine coupling constant (hfc) was determined.
View Article and Find Full Text PDFSci Total Environ
January 2025
School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
The efficacy of ferrihydrite in remediating Cd-contaminated soil is tightly regulated by Fe(II)-induced mineralogical transformations. Despite the common coexistence of iron minerals such as goethite and lepidocrocite, which can act as templates for secondary mineral formation, the impact of these minerals on Fe(II)-induced ferrihydrite transformation and the associated Cd fate have yet to be elucidated. Herein, we investigated the simultaneous evolution of secondary minerals and Cd speciation during Fe(II)-induced ferrihydrite transformation in the presence of goethite versus lepidocrocite.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk 660036, Russian Federation.
The crystal structures and hyperfine magnetic parameters of EuFe(BO) and mixed EuLaFe(BO) were studied over a wide temperature range in order to analyze correlations of the structural and magnetic features and the phase transitions in multiferroic compounds of the rare-earth iron borate family. The chemical compositions of the crystals are reported from X-ray fluorescence analysis. The crystal structures of EuFe(BO) and EuLaFe(BO) were determined using single-crystal X-ray diffraction in the temperature range 25-500 K.
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January 2025
Faculty of Biochemistry, Biophysics and Biotechnology, Department of Plant Physiology and Biochemistry, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
In this work a novel method for synthesis of 1,8-dihydroxynaphthalene melanin was presented, as well as the physicochemical properties, molecular structure, and characteristics of the pigment. The proposed synthesis protocol is simple and cost-effective with no enzymes or catalysts needed. The final product is not adsorbed on any surface, since the pigment is the result of autooxidation of 1,8-dihydroxynaphthalene.
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