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At least 523 records · Page 29

Absolute cross section of the C 12 ( p , γ ) N 13 reaction

Solar neutrino measurements have recently reached a level of sensitivity such that CNO fluxes can now be experimentally determined. While these first measurements are still only sensitive to the higher energy neutrinos resulting from the β + decays of 15 Ο produced by the 14 Ν ⁡( p ,$\gamma$)⁢ 15 O reaction, future measurements will work towards detection of neutrinos from the β + decay of 13 N from the 12 C ⁡( p ,$\gamma$)⁢ 13 N reaction. Here, this paper reports on a recent measurement of the 12 C ⁡( p ,$\gamma$)⁢ 13 N reaction covering a broad laboratory energy range between 1.0 and 2.5 MeV. The measurement was made to better determine the overall normalization of the absolute cross section and to explore the interference effects between the two broad, overlapping resonances at proton energies of 0.460 and 1.689 MeV and the direct capture to the ground state of 13 N in the framework of a multichannel R -matrix analysis. This work takes into account previous radiative capture as well as elastic 12 C ( p , p ) 12 C scattering data, making uncertainty estimations using a Bayesian framework, to determine a reliable extrapolation of the low energy S factor towards the stellar energy range of CNO hydrogen burning. These new experimental results, and a detailed investigation of the past literature data, suggest that the resonant component of the cross section should be 30% lower than previously accepted.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Measurement of the energy-differential 35 Cl( n, p 0 ) 35 S cross section via the ratio with 6 Li( n, α ) 3 H

Knowledge of the neutron-induced 35 Cl ⁢(n, x) cross sections is vital to the design and certification of molten chloride fast reactors (MCFRs) since the 35 Cl (n, p 0 ) 35 S reaction is believed to be a significant reactor poison. However, recently published measurements are inconsistent with each other and with evaluation. Here, the goal of this work is to measure the 35 Cl (n, p 0 ) reaction cross section using a technique that is different from recent measurements. The experiment was conducted at Lawrence Berkeley National Laboratory's (LBNL) 88-Inch Cyclotron using thick target deuteron breakup from a 14 MeV deuteron beam. Energy-differential 35 Cl (n, p 0 ) 35 S cross sections were obtained via ratio with the 6 Li (n, a)⁢ 3 H reaction using an active target experiment with a Cs 2 ⁢LiYCl 6 (CLYC) scintillator. The 35 Cl (n, p 0 ) reaction cross section was measured from 2.02 to 7.46 MeV. The results are consistent with Kuvin et al., confirming a roughly 50% reduction in magnitude relative to the ENDF/B-VIII.0 evaluation. These data provide new insight into the role of natural Cl as an MCFR poison. The reduction of the 35 Cl (n, p 0 ) reaction cross section compared to evaluation suggests that MCFR criticality is less sensitive to Cl enrichment. This may in turn reduce building and operating costs since isotope separation may not be needed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Metamorphic Tunnel Junctions Grown Via MOCVD Designed for GaAs 0.75 P 0.25 /Si Tandem Solar Cells

A high-performance metamorphic Al 0.2 Ga 0.8 As 0.75 P 0.25 /GaAs 0.75 P 0.25 heterojunction tunnel junction structure was developed for application to monolithic epitaxial GaAs 0.75 P 0.25 /Si 1.7 eV/1.1 eV bandgap tandem solar cells produced via metal-organic chemical vapor deposition. Doping optimization focused on both bulk doping concentrations and mitigating the transient incorporation effects that otherwise causes non-abrupt doping profiles in the Te doped layer. Furthermore, these efforts resulted in a fully-relaxed metamorphic tunnel diode at the target lattice constant having a peak tunneling current density (JP) of 279.1 A·cm –2 and a zero-bias resistance area product (RA) of 3.0×10 –4 Ω·cm 2 . After post-growth annealing to emulate the thermal load of the GaAs 0.75 P 0.25 top cell growth and elimination of the performance enhancing carbon activation anneal, the device achieved JP = 13.1 A·cm –2 and RA = 1.5×10 –3 Ω·cm 2 . These worst-case values are very promising as they enable the operation of GaAs 0.75 P 0.25 /Si tandems under one-sun AM1.5G illumination with negligible series resistance and at AM1.5D concentrations up to 240 suns with only 0.1% absolute efficiency loss.

14 SOLAR ENERGY↗

Metabolic engineering of p –hydroxybenzoate in poplar lignin

Ester-linked p-hydroxybenzoate occurs naturally in poplar lignin as pendent groups that can be released by mild alkaline hydrolysis. These ‘clip-off’ phenolics can be separated from biomass and upgraded into diverse high-value bioproducts. We introduced a bacterial chorismate pyruvate lyase gene into transgenic poplar trees with the aim of producing more p-hydroxybenzoate from chorismate, itself a metabolic precursor to lignin. By driving heterologous expression specifically in the plastids of cells undergoing secondary wall formation, this strategy achieved a 50% increase in cell-wall-bound p-hydroxybenzoate in mature wood and nearly 10 times more in developing xylem relative to control trees. Comparable amounts also remained as soluble p-hydroxybenzoate-containing xylem metabolites, pointing to even greater engineering potential. Mass spectrometry imaging showed that the elevated p-hydroxybenzoylation was largely restricted to the cell walls of fibres. Finally, transgenic lines outperformed control trees in assays of saccharification potential. Here, this study highlights the biotech potential of cell-wall-bound phenolate esters and demonstrates the importance of substrate supply in lignin engineering.

4-hydroxybenzoic acid↗

Direct comparison of using a Z -transformation instead of the traditional $Q^2$ for extraction of the proton radius from $e-p$ scattering data

A discrepancy in the determination of the proton’s charge radius, r p , between muonic hydrogen spectroscopy versus classic atomic spectroscopy and electron scattering data has become known as the proton radius puzzle. Extractions of r p from electron scattering data require determination of the slope of the proton’s charge form factor, $G$$^{p}_{E}$, in the limit of Q 2 → 0 through fitting and extrapolation. Some works have presented the Z-transformation fitting technique as the best choice for this type of extraction due to the true functional form of $G$$^{p}_{E}$ being mathematically guaranteed to exist within the parameter-space of the fit function. In this work, we test this claim by examining the mathematical bias and variances introduced by this technique as compared to the more traditional Q 2 fits using statistically sampled $G$$^{p}_{E}$ parameterizations with known input radii. Furthermore, our tests conclude that the quality of the Z-transformation technique depends on the range of data used. In the case of new experiments, the fit function and technique should be selected in advance by generating realistic pseudodata and assessing the power of different techniques.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

High Voltage Regrown GaN P-N Diodes Enabled by Defect and Doping Control

This project studied and implemented methods to form GaN p-n diodes using selective area regrowth to achieve selective area doping. Successful selective area doping of GaN p-n diodes is an enabling factor to realize more advanced devices such as vertical transistors. The general challenge to selective area regrowth of GaN is that the primary etch method, inductively coupled plasma (ICP), damages the crystal and causes high leakage when didoes are formed by regrowth on the etched surface. Our approach used low damage etch methods following ICP etch to remove crystal damage and reduced leakage in the regrown diode. This project demonstrated 1.6 kV etched-and-regrown GaN p-n diodes using planar (non-selective) regrowth and 840 V etched-and-regrown p-n diodes using selective area regrown. Enabling factors were use of a low-damage reactive ion etch (RIE) to remove damage caused by the primary ICP etch combined with a multi-step junction terminal extension (JTE) process. Deep level defect investigation quantitatively correlated a deep level near the middle of the GaN band gap with ICP etch-induced leakage that was greatly mitigated by using a slow, low damage RIE process. This research is economically feasible for commercialization because the processes used in this project, including substrate type and source, epitaxial crystal growth and fabrication techniques are all standard to the GaN semiconductor industry. The fundamental understanding and foundational ability to produce kV-class GaN p-n diodes through etch-and-regrowth provides a path to realize high power, high efficiency GaN power switches that can significantly outperform commercial devices for next-generation electrical power conversion and transmission systems.

36 MATERIALS SCIENCE↗

Understanding the Mechanism of Light and Elevated Temperature Induced Degradation of p-type Silicon Solar Cells (Final Report)

Light- and elevated-temperature-induced degradation (LeTID) was first discovered in multicrystalline Si (mc-Si) solar cells and was initially attributed to metal impurities. Later, LeTID was reported in Czochralski (Cz) and float-zone (FZ) Si, and is considered as an important efficiency loss mechanism in p-type passivated emitter rear contact (p-PERC) Cz Si solar cells. LeTID causes ~10% relative and permeant efficiency losses in these cells in warmer climate regions where the module temperature is > 50 °C. Unlike light-induced degradation (LID), which is also observed in p-PERC cells, LeTID is slower and takes weeks to months in the field to saturate. Another difference compared to LID is that regeneration in LeTID proceeds very slowly, and field regeneration could take > 25 years — essentially the life of the module. Unlike B-O defects that are responsible for LID, neither B nor O impurities are directly involved in LeTID. LeTID appears to be unique to p-type Si, and is also observed in Ga-doped Si. Currently, most experimental evidence relates LeTID to the injection of hydrogen present in the dielectric surface passivation layers, such as SiN x and Al 2 O 3 , into the monocrystalline Si (c-Si) bulk during the fast-firing step. The involvement of hydrogen is further strengthened by controlled studies that show that increasing the amount of hydrogen in the dielectric during fast-firing increases the degree of LeTID. Similar to LID, a regeneration process has been discovered for LeTID. Regeneration of LeTID defects occurs when samples are exposed to 2–4 Suns illumination at elevated temperatures of 140–220 °C for 2–15 hr. Given the slower kinetics of LeTID and sample regeneration compared to LID, this poses a challenge for the manufacturing and field reliability of p-PERC cells, which will be the leading photovoltaic technologies over the next decade. Therefore, there is a need to understand LeTID and develop strategies to mitigate this effect. The defect responsible for LeTID has been extensively studied with over 100 publications, but direct spectroscopic evidence of this defect’s structure is lacking. Without an atomistic understanding of the LeTID defect, it is difficult to assess the long-term efficacy of the current industrial mitigation strategies. This, in turn, has implications on energy production for tens of gigawatts of these cells that will be deployed yearly worldwide. Using electron paramagnetic resonance, we identified a defect associated with LeTID with a g-value of 2.006, which we attribute to an Si dangling bond in an extended defect such as a vacancy agglomerate with H possibly within or in close vicinity. These vacancy agglomerates are likely created during the firing process, during which time H atoms are also injected into the bulk from the hydrogenated SiN x dielectric layer. Our atomistic-level insight shows that the LeTID defect can be mitigated by targeted intrinsic defect engineering of the c-Si material through a slower pull rate of the Cz ingot or 1000 °C oxygen ambient processing of the Si wafer to reduce the vacancy concentration. This project was a collaborative effort between the Colorado School of Mines and the National Renewable Energy Laboratory.

14 SOLAR ENERGY↗

Hierarchical Bayesian Thermonuclear Rate for the 7 Be(n,p) 7 Li Big Bang Nucleosynthesis Reaction

Big Bang nucleosynthesis provides the earliest probe of standard model physics, at a time when the universe was less than 1000 seconds old. It determines the abundances of the lightest nuclides, which give rise to the subsequent history of the visible matter in the universe. This work derives new 7 Be(n,p) 7 Li thermonuclear reaction rates based on all available experimental information. This reaction sensitively impacts the primordial abundances of 7 Be and 7 Li during big bang nucleosynthesis. We critically evaluate all available data and disregard experimental results that are questionable. For the nuclear model, we adopt an incoherent sum of single-level, two-channel, R -matrix approximation expressions, which are implemented into a hierarchical Bayesian model, to analyze the remaining six data sets we deem most reliable. In the fitting of the data, we consistently model all known sources of uncertainty, including discrepant absolute normalizations of different data sets, and also take the variation of the neutron and proton channel radii into account, hence providing less biased estimates of the 7 Be(n,p) 7 Li thermonuclear rates. From the resulting posteriors, we extract R -matrix parameters ($E_r, γ^2_n, γ^2_p$) and derive excitation energies and partial and total widths. Our fit is sensitive to the contributions of the first three levels above the neutron threshold. Reaction rates were computed by integrating 10,000 samples of the reduced cross section. Our 7 Be(n,p) 7 Li thermonuclear rates have uncertainties between 1.5% and 2.0% at temperatures of ≤1 GK. Finally, we compare our rates to previous results and find that the 7 Be(n,p) 7 Li rates most commonly used in big bang simulations have uncertainties that are too optimistic.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Exoproteomics Reveals Outer Membrane Vesicle Mediated Catabolism of Lignin-Derived Aromatics by P. putida KT2440

Lignin is an abundant component of plant cell walls which is heterogeneous and highly resistant to degradation. Biological funneling of lignin via microbes represents an efficient approach for reducing chemical heterogeneity and generating molecules which can be valorized into performance-advantaged materials. Pseudomonas putida KT2440 (P. putida) catabolizes lignin-derived aromatic monomers rapidly and efficiently via the b-ketoadipate (bKA) pathway and our data suggest P. putida may depolymerize HMW lignin as well [1]. The mechanism by which HMW lignin is depolymerized by bacteria remains unknown. Intriguingly, we found that P. putida secretes outer membrane vesicles (OMVs) of two distinct sizes in the presence of lignin. Here, we describe the temporal proteome of OMVs and the vesicle-free secretome (VFS) in the presence or absence of lignin. Enzymes involved in aromatic catabolism via the bKA pathway are temporally enriched into OMVs in the presence of lignin. Isolated OMVs enhance growth of P. putida mutants unable to grow on model lignin-derived aromatics, and turnover protocatechuic acid in vitro. Together, this work leads us to hypothesize mechanisms by which OMVs contribute to extracellular aromatic catabolism by P. putida. Ongoing and future work seeks to further understand this phenomena in the context of both fundamental an applied lignin conversion research areas.

09 BIOMASS FUELS↗

P{sub N} source expansion nodal method in MPACT for boiling water reactors

This paper describes the one-node P{sub N}-Source Expansion Nodal Method (SENM) axial solver for the 2D/1D method recently implemented in MPACT to support Boiling Water Reactors (BWR) analysis. Since the BWR has a more complicated design and strong burnable absorber, the existing PN-Nodal Expansion Method (NEM) axial solver in MPACT may not be sufficient to accurately represent the intranodal flux and source profiles for BWRs. The one-node P{sub N}-SENM has been implemented in this work to reduce the axial spatial discretization error for BWRs. From numerical results, we verify that the P{sub N}-SENM can improve the accuracy of the pin power prediction, and confirm that P{sub N}-SENM can use more than a 1.5 times larger axial mesh size than P{sub N}-NEM to have similar accuracy for the BWR GE14 3D assembly problem. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Measurement of C P Violation in B 0 → ψ ( → ℓ + ℓ − ) K S 0 ( → π + π − ) Decays

A measurement of time-dependent C P violation in the decays of B 0 and B ¯ 0 mesons to the final states J / ψ ( → μ + μ − ) K S 0 , ψ ( 2 S ) ( → μ + μ − ) K S 0 and J / ψ ( → e + e − ) K S 0 with K S 0 → π + π − is presented. The data correspond to an integrated luminosity of 6 fb − 1 collected at a center-of-mass energy of s = 13 TeV with the LHCb detector. The C P -violation parameters are measured to be S ψ K S 0 = 0.717 ± 0.013 ( stat ) ± 0.008 ( syst ) and C ψ K S 0 = 0.008 ± 0.012 ( stat ) ± 0.003 ( syst ) . This measurement of S ψ K S 0 represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the C P -violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗

Z-boson production in p-Pb collisions at $ \sqrt{s_{\mathrm{NN}}} $ = 8.16 TeV and Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}} $ = 5.02 TeV

Measurement of Z-boson production in p-Pb collisions at $ \sqrt{s_{\mathrm{NN}}} $ = 8 . 16 TeV and Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}} $ = 5 . 02 TeV is reported. It is performed in the dimuon decay channel, through the detection of muons with pseudorapidity - 4 < η μ < - 2 . 5 and transverse momentum $ {p}_{\mathrm{T}}^{\mu } $ > 20 GeV/ c in the laboratory frame. The invariant yield and nuclear modification factor are measured for opposite-sign dimuons with invariant mass 60 < m μμ < 120 GeV/ c 2 and rapidity 2 . 5 < $ {y}_{\mathrm{cms}}^{\mu \mu} $ < 4. They are presented as a function of rapidity and, for the Pb-Pb collisions, of centrality as well. The results are compared with theoretical calculations, both with and without nuclear modifications to the Parton Distribution Functions (PDFs). In p-Pb collisions the center-of-mass frame is boosted with respect to the laboratory frame, and the measurements cover the backward ( - 4 . 46 < $ {y}_{\mathrm{cms}}^{\mu \mu} $ < - 2 . 96) and forward (2 . 03 < $ {y}_{\mathrm{cms}}^{\mu \mu} $ < 3 . 53) rapidity regions. For the p-Pb collisions, the results are consistent within experimental and theoretical uncertainties with calculations that include both free-nucleon and nuclear-modified PDFs. For the Pb-Pb collisions, a 3 . 4 σ deviation is seen in the integrated yield between the data and calculations based on the free-nucleon PDFs, while good agreement is found once nuclear modifications are considered.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Ab initio investigation of the Li 7 ( p , e + e - ) Be 8 process and the X17 boson

Observations of anomalies in the electron-positron angular correlations in high-energy decays in 4 He, 8 Be, and 12 C have been reported recently by the ATOMKI collaboration. These could be explained by the creation and subsequent decay of a new boson with a mass of ≈ 17MeV. Theoretical understanding of pair creation in the proton capture reactions used in these experiments is important for the interpretation of the anomalies. We apply the ab initio no-core shell model with continuum (NCSMC) to the proton capture on 7 Li. The NCSMC describes both bound and unbound states in light nuclei in a unified way with chiral two- and three-nucleon interactions as the only input. We investigate the structure of 8 Be, the p+ 7 Li elastic scattering, the 7 Li(p,y)⁢ 8 Be cross section, and the internal pair creation 7 Li ⁢(p,e + ⁢e - ) 8 Be. Here we discuss the impact of a proper treatment of the initial scattering state on the electron-positron angular correlation spectrum and compare our results to available ATOMKI data sets. Finally, we calculate 7 Li ⁢(p,X)⁢ 8 Be cross sections for several proposed models of the hypothetical X17 particle.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

First Direct Measurement Constraining the Ar 34 ( α , p ) K 37 Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars

The rate of the final step in the astrophysical αp process, the 34 Ar(α,p) 37 K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. Here, we present the first direct measurement constraining the 34Ar(α,p)37K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the 34 Ar,Cl(α,p) 37 K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The 34 Ar(α,2p) 36 Ar cross section, which can be exclusively attributed to the 34 Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Measurements of the Elliptic and Triangular Azimuthal Anisotropies in Central He 3 + Au , d + Au and p + Au Collisions at s N N = 200 GeV

The elliptic (v 2 ) and triangular (v 3 ) azimuthal anisotropy coefficients in central 3He + Au, d + Au, and p + Au collisions at $\sqrt{S_{NN}}$ = 200 GeV are measured as a function of transverse momentum (P T ) at midrapidity (|n| < 0.9) via the azimuthal angular correlation between two particles both at |n| < 0.9 while the v 2 (P T ) values depend on the colliding systems, the v 3 (P T ) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. Furthermore, these results also provide stringent constraints for the hydrodynamic modeling of these systems.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Azimuthal correlations of prompt D mesons with charged particles in pp and p–Pb collisions at \({\sqrt{s_\mathrm{NN}}} = 5.02\ \hbox {TeV}\)

The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at \(\sqrt{s} =5.02\ \hbox {TeV}\) and p–Pb collisions at \(\sqrt{s_{\mathrm{NN}}} = 5.02\ \hbox {TeV}\) with the ALICE detector at the LHC is reported. The \(\mathrm{D}^{0}\) , \(\mathrm{D}^{+} \) , and \(\mathrm{D}^{*+} \) mesons, together with their charge conjugates, were reconstructed at midrapidity in the transverse momentum interval \(3< p_\mathrm{T} < 24\ \hbox {GeV}/c\) and correlated with charged particles having \(p_\mathrm{T} > 0.3\ \hbox {GeV}/c\) and pseudorapidity \(|\eta | < 0.8\) . The properties of the correlation peaks appearing in the near- and away-side regions (for \(\Delta \varphi \approx 0\) and \(\Delta \varphi \approx \pi \) , respectively) were extracted via a fit to the azimuthal correlation functions. The shape of the correlation functions and the near- and away-side peak features are found to be consistent in pp and p–Pb collisions, showing no modifications due to nuclear effects within uncertainties. The results are compared with predictions from Monte Carlo simulations performed with the PYTHIA, POWHEG+PYTHIA, HERWIG, and EPOS 3 event generators.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Charm fragmentation fractions and $\mathbf {c\overline{c}}$ cross section in p–Pb collisions at $\mathbf {\sqrt{s _{NN}}=5.02 TeV}$

The total charm-quark production cross section per unit of rapidity dσ($\mathbf {c\overline{c}}$)/dy, and the fragmentation fractions of charm quarks to different charm-hadron species f(c → h c ), are measured for the first time in p–Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV at midrapidity (–0.96 < y < 0.04 in the centre-of-mass frame) using data collected by ALICE at the CERN LHC. The results are obtained based on all the available measurements of prompt production of ground-state charm-hadron species: D 0 , D + , D$^{+}_{s}$, and J/ψ mesons, and Λ$^{+}_{c}$ and $Ξ$$^{0}_{c}$ baryons. The resulting cross section is dσ($\mathbf {c\overline{c}}$)/dy = 219.6 ± 6.3 (stat.) $^{+10.5}_{–11.8}$ (syst.) $^{+8.3}_{–2.9}$ (extr.) ± 5.4 (BR) ± 4.6 (lumi.) ± 19.5 (rapidity shape) + 15.0 (Ω$^{0}_{c}$) mb, which is consistent with a binary scaling of pQCD calculations from pp collisions. The measured fragmentation fractions are compatible with those measured in pp collisions at $\sqrt{s_{NN}}$ = 5.02 and 13 TeV, showing an increase in the relative production rates of charm baryons with respect to charm mesons in pp and p–Pb collisions compared with e + e – and e – p collisions. The p T -integrated nuclear modification factor of charm quarks, R pPb ($\mathbf {c\overline{c}}$) = 0.91 ± 0.04 (stat.) $^{+0.08}_{–0.09}$ (syst.) $^{+0.05}_{–0.03}$ (extr.) ± 0.03 (lumi.), is found to be consistent with unity and with theoretical predictions including nuclear modifications of the parton distribution functions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Materials Data on P(HO)3 by Materials Project

H3PO3 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a distorted tetrahedral geometry to one H+0.33+ and three O2- atoms. The P–H bond length is 1.40 Å. There is one shorter (1.52 Å) and two longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded in a distorted tetrahedral geometry to one H+0.33+ and three O2- atoms. The P–H bond length is 1.40 Å. There are a spread of P–O bond distances ranging from 1.52–1.57 Å. There are six inequivalent H+0.33+ sites. In the first H+0.33+ site, H+0.33+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.55 Å) H–O bond length. In the second H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one P5+ atom. In the third H+0.33+ site, H+0.33+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.53 Å) H–O bond length. In the fourth H+0.33+ site, H+0.33+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.58 Å) H–O bond length. In the fifth H+0.33+ site, H+0.33+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.56 Å) H–O bond length. In the sixth H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one P5+ atom. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to one P5+ and two H+0.33+ atoms. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one P5+ and two H+0.33+ atoms.

36 MATERIALS SCIENCE↗