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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Fast Algorithm for Evaluating Critical Current of High-Temperature Superconducting Pancake Coil

Second-generation (2G) high-temperature superconducting (HTS) tapes are now capable of carrying very high transport current and promising for a wide range of applications. The critical current of HTS coils is important for applications, such as superconducting electric machines, superconducting magnetic energy storage, and superconducting magnets. Therefore, precisely and quickly calculating critical current of HTS coils is very important for designing HTS devices. This paper provides a fast algorithm for evaluating critical current of HTS pancake coil. The fast algorithm is realized through a stationary model, which is based on finite element method (FEM) software. The stationary model means that the model is solved by stationary study instead of time-dependent study. To validate this method, a pancake HTS coil was wound and its critical current was measured. Meanwhile, an axial symmetric stationary model was built according to the geometry of the measured HTS coil. By comparing measured and calculated results, the effectiveness of the stationary model was demonstrated. Moreover, the stationary model is compared with H formulation model. The calculated results by the two models are nearly the same. However, by using stationary calculation, the stationary model can remarkably speed up the computational process. Due to the advantage of calculating speed, the stationary model can be used to characterize and design large-scale HTS applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Hydrogen Annealing Effect on the Magnetic Properties of ZnCoO/MoS{sub 2} Hybrid

The ZnCoO/MoS{sub 2} hybrid is successfully synthesized through a general and facile process. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectra reveal that the hybrid consists of wurtzite ZnCoO and few layers of MoS{sub 2}, which shows a paramagnetic property. In contrast, the hybrid presents clear magnetic hysteresis at room temperature with a H{sub 2} post-annealing process. No Co metal nanoclusters can be identified by XRD and HRTEM. The red shift of E{sub 2g}{sup 1} and A{sub 1g} peak indicates the strain effect induced by H{sub 2} annealing. On the other hand, the disappeared peak at 477 cm{sup −1} can be ascribed to the modification of the interface and surface state of the ZnCoO. Temperature-dependent Raman spectroscopies demonstrate the significant H{sub 2} annealing effect on the structural properties of ZnCoO/MoS{sub 2} hybrid. The interplay between the electron interaction at the interface and oxygen vacancies of ZnCoO can be responsible for the magnetic properties of the ZnCoO/MoS{sub 2} hybrid. The tunable magnetic properties have a promising application in multifunctional MoS{sub 2}-based semiconductor and spintronic devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Magnetic and Dielectric Properties of Y{sub 3−x}Sm{sub x}Fe{sub 5}O{sub 12} (x = 0.0 to 3.0)

Single-phase polycrystalline samples of Y{sub 3−x}Sm{sub x}Fe{sub 5}O{sub 12} (x = 0.0–3.0) were prepared by using a solid-state reaction method. The lattice constant is found to increase from 12.372 Å for x = 0.0 to 12.524 Å for x=3.0. The substitution of Sm{sup 3+} at Y{sup 3+} site is confirmed from the red shift of Raman F{sub 2g} mode. Magnetization loops measured at room temperature and the analysis of initial magnetization curves show that saturation magnetization value decreases with an increase in Sm concentration due to the possible antiferromagnetic interaction. On the other hand, temperature variation of magnetization plots shows that all the samples exhibit ferrimagnetic transition with transition temperature in the range of 550 K for x = 0.0 to 573 K for x=3.0. The dielectric constant increases upon Sm substitution, and the analysis of impedance and dielectric spectra shows the contribution of both grains and grain boundaries.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Effect of Ag Addition on the Surface Topography and the Vibrational Dynamics of MgB{sub 2}

We fabricated MgB{sub 2} samples with Ag additions using in situ solid-state reaction via a single-step sintering to study the effect of Ag on the structural, vibration, and superconducting properties of MgB{sub 2} samples. Ag addition to MgB{sub 2} resulted in a significant improvement in J{sub c} although no appreciable effect was observed in the lattice parameters and the superconducting transition temperature T{sub c}. Dramatic increase in the grain size was observed with Ag addition and topographic measurements with atomic force microscopy revealed the formation of Ag–Mg nanoparticles 5–20 nm in size at 2 and 4 wt% Ag additions. The fact that these samples showed high J{sub c} values suggests that the nanoparticles formed as a result of Ag addition are responsible for enhanced flux pinning. Raman spectroscopy measurements showed that Ag additions also increased disorder in the system and thereby affected the line width of the Raman active E{sub 2g} mode.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Possible Origin of Ferromagnetism in Transition Metal Doped Zirconia

We have studied the electronic structure and magnetic properties of cubic zirconia (c-ZrO{sub 2}) with cobalt (Co) or nickel (Ni) doping using density functional theory (DFT) calculations. The pure c-ZrO{sub 2} is a nonmagnetic insulator with a wide bandgap. The calculated results reveal that isolated Co or Ni atom can both produce the local magnetic moment in c-ZrO{sub 2}. And the isolated Co atom can introduce a magnetic moment of about 0.98 μ{sub B}, while the Ni atom is 2.85 μ{sub B}. The impurity peaks can be formed in the bandgap. Our studies show that the magnetic moments mainly result from d orbitals of the impurity atoms. And the spin-up electrons will be arranged in t{sub 2g} orbitals under the ligand field of O{sub h} group in Co- or Ni-doped c-ZrO{sub 2}. Obviously, this will lead to a high-spin state (S = 1/2 or 1). The studies of magnetic coupling reveal that the two Co atoms in c-ZrO{sub 2} are not always coupled ferromagnetically at different distances. And the system will be in a spin singlet state (S = 0) when the distance is 6.209 or 7.170 Å between two Co atoms. However, the two Ni atoms in c-ZrO{sub 2} are always coupled ferromagnetically at all distances. So we can conclude that the Ni-doped c-ZrO{sub 2} is more suitable for spintronic material than Co doping. These results are significant for spintronics.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Influence of AC Loss on Stress and Strain of Superconducting Coils

The second-generation (2G) high-temperature superconducting (HTS) coated conductors (CC) are increasingly used in power systems recently, especially in large-capacity superconducting magnetic energy storage (SMES). HTSCC in superconducting energy storage coil is subjected to thermal stress which is caused by thermal contraction due to AC loss. The thermal stress will degrade the critical currents and may cause the displacement of the superconducting coil and insulating epoxy resin. In this work, the AC loss of the superconducting coil is firstly obtained by finite element method (FEM) software COMSOL with the method of iterative conductivity. Furthermore, the effect of AC loss on the superconducting coil is thus analyzed by solving the coupling problems which include magnetic field, mechanical behaviors, and heat transfer in solids. The result shows that the AC loss of the superconducting coil is concentrated in the middle of the coil and the maximum AC loss density is 5.96 × 10{sup 5} W/m{sup 3}; the maximum stress laid at the inner radius of the coil and the maximum stress is 0.01 MPa.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Fabrication and Tests of a Resistive-Type Superconducting Fault Current Limiter Module Based on Coated Conductors

The resistivetype superconducting fault current limiter (R-SFCL) is simple in structure, near zero impedance at normal state and can be quickly triggered by the fault current. Thus, it is a possible solution to limit the fault current in the power grid. In this paper, we report the fabrication and test for an R-SFCL module The R-SFCL module consists of seven bifilar coils connected in parallel, which were wound with two parallel 2G tapes. A 5mm spacer was co-wound between adjacent turns to act as the highvoltage insulation. In the tests, we test the current distribution among the bifilar coils, and then simulated short-circuit tests were conducted on the module to obtain its performance under fault current surge.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Influence of Al doping concentration on the opto-electronic chattels of SnS thin films readied by NSP

Herein, we limelight the key features of SnS thin films coated by spray pyrolysis process with different Al doping concentrations. The SnS thin films coated with different Al concentration (0, 2, 4, 6 at wt%) were characterized by various techniques. Structural parameters studied by XRD data revealed that all the prepared films were orthorhombic crystal structure with (111) as a preferential direction. Raman spectroscopy showed the presence of Ag, B{sub 1g}, B{sub 2g}, and B{sub 3g} vibration modes at their corresponding wave numbers. Concentration dependent granular change of Al:SnS films were shown by AFM images. The presence of Sn, S and Al element without any other impurities was confirmed through EDAX picture. UV studies revealed the shrinkage of band gap from 1.97 to 1.72 eV on increasing the Al doping concentration from 0% to 4 at wt%. Room temperature PL showed a high intense red shift, as emission observed at 722 nm for 4% of Al doped SnS thin film. Hall measurements exhibited p-type conducting nature of undoped and Al doped SnS films. The films showed a lowest resistivity of 2.695×10{sup −1} Ω cm for 4 at wt% Al doping concentration. 0.093% efficiency was obtained for the solar cell device fabricated by 4 at wt% of Al doped SnS thin film.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Exact solutions of Dirac equation on a static curved space–time

In this work we study the Dirac equation in a curved static space–time, where the metric depends on two arbitrary functions f(r) and g(r), namely the line element is ds{sup 2}=e{sup 2f(r)}dt{sup 2}-e{sup 2g(r)}dr{sup 2}-r{sup 2}dθ{sup 2}-r{sup 2}sin{sup 2}θdϕ{sup 2}. We exactly solve the angular equation for arbitrary f(r) and g(r). Then, we uncouple the radial component of the spinor for a metric model defined by f=g and find the exact solutions for three quantum systems: Hydrogen atom, Dirac–Morse oscillator and a linear radial potential by V(r)=ar.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Cost details from front-end engineering design of piperazine with the advanced stripper

This Front-End Engineering Design (FEED) was funded by the U.S. Department of Energy (DOE) to estimate the cost to capture and compress 90% of the CO 2 from an existing natural gas combined cycle (NGCC) in Denver City, Texas, USA. The FEED used the PZAS (Piperazine with the Advanced Stripper) 2G amine scrubbing technology developed and modeled by The University of Texas at Austin. This FEED is unique in providing more public cost details than other FEEDs funded by DOE. The primary objective of the FEED was to provide a comprehensive estimate for the total installed cost of the capture plant. The estimated capital cost of NGCC at the Mustang Station is $\$727$ million for a capacity of 460 MW and 1.6 million tonnes CO 2 /yr. This includes a contingency of $\$104.6$ million and a contractor’s profit of $\$60.1$ million. The total direct field cost is $\$384.1$ million. With an optimistic fuel value of $\$3$/MMBtu, the estimated cost of capture varies from $\$85$/t at 4% IRR/85% load to $\$170$/t at 10% IRR/52% load. Air cooling is technically feasible but expensive. The air cooling systems for the water wash and pump-around intercooling account for 23.4% of the direct cost. The gas-fired boilers represent only 4% of the direct costs, but steam extraction would reduce energy cost, free up cooling water, and reduce the direct costs of processing additional flue gas and CO 2 from the boilers. The absorbers represent 9.6% of the direct cost in this FEED with no direct contact cooler and only 7.6 m of packing. Furthermore, the solvent cross exchangers are less expensive than expected (2.5% of direct costs). Doubling the number of these exchangers could reduce the heat duty from 3.0 to 2.5 GJ/t CO 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

The orbital effect on the anomalous magnetism and evolution in La $x$ Y 1-$x$ VO 3 (0 ≤ $x$ ≤ 0.2) single crystals

The orbital effect on the anomalous magnetism and evolution of single crystals with low La doping, La $x$ Y 1-$x$ VO 3 ($x$ = 0, 0.1, and 0.2), has been studied using single-crystal X-ray diffraction, specific heat, magnetization, and Raman-scattering techniques. It is found that substituting Y 3+ by La 3+ increases the degeneracy of the $yz/zx$ orbitals and decreases the Jahn-Teller distortion. These weakens the G-type (antiphase ordering along the c axis) orbital ordering phase. Meanwhile, the substituting decreases the magnetism entropy, indicating the shrinking of the t 2g and e g orbital hybridization, eventually destabilizing the C-type (in-phase ordering along the c axis) antiferromagnetic ordering phase. In addition, the mechanism for the shrinking of the diamagnetism with increasing $x$ is analyzed. In conclusion, it may attribute to the competition between the antisymmetric Dzyaloshinsky–Moriya interaction and the single-ion anisotropy.

36 MATERIALS SCIENCE↗
DOE OSTI2016

An investigation of the optical properties and water splitting potential of the coloured metallic perovskites Sr{sub 1−x}Ba{sub x}MoO{sub 3}

The solid solution Sr{sub 1−x}Ba{sub x}MoO{sub 3} (x=0.00, 0.025, 0.050, 0.075, 0.100 and 1.00) has been synthesised. Rietveld refinement of X-ray diffraction data shows that all materials crystallise with cubic (Pm-3m) symmetry and that a miscibility gap exists from x=0.1–1.0. The optical properties of the metallic perovskites Sr{sub 1−x}Ba{sub x}MoO{sub 3} have been investigated by a combination of UV–vis spectroscopy and density functional theory (DFT). Upon increasing x from 0 to 1 in Sr{sub 1−x}Ba{sub x}MoO{sub 3} there is a reduction in the measured band gap from 2.20 eV to 2.07 eV. The measured band gap is attributed to the electronic transition from the Mo 4d t{sub 2g} band to the e{sub g} band. The potential of SrMoO{sub 3} and BaMoO{sub 3} as water-splitting photocatalysts was explored but there was no evidence of hydrogen or oxygen evolution, even with the presence of a Pt co-catalyst. - Graphical abstract: Ultraviolet–visible absorbance spectra (converted from diffuse reflectance spectra) for SrMoO{sub 3} and BaMoO{sub 3}. - Highlights: • The solid solution Sr{sub 1-x}Ba{sub x}MoO{sub 3} has been synthesised. • A miscibility gap exists from x=0.1–1.0 in Sr{sub 1−x}Ba{sub x}MoO{sub 3.} • Upon increasing x from 0 to 1 in Sr{sub 1−x}Ba{sub x}MoO{sub 3} there is a reduction in the measured band gap from 2.20 eV to 2.07 eV. • The potential of SrMoO{sub 3} and BaMoO{sub 3} as water-splitting photocatalysts was explored but there was no evidence of hydrogen or oxygen evolution, even with the presence of a Pt co-catalyst.

36 MATERIALS SCIENCE↗
DOE OSTI2019

On the Mn 4+ R-line emission intensity and its tunability in solids

The spectroscopic properties of Mn 4+ ions in solids are analyzed to establish key parameters that are responsible for the energy and the intensity of the 2 E g → 4 A 2g zero-phonon emission transition (R-line). These two factors of the emission spectrum are critical in determining the phosphor luminosity or brightness. The emission energy is chiefly determined by the “Mn 4+ -ligand” bonding covalence. In fluorides, the Mn-F bonding covalence is weak, and the R-line occur at higher energy. In oxides, the stronger Mn-O bonding covalence reduces the energy of the 2 E g state. In oxides, the R-line shifts to higher energy with increasing local distortion of the MnO 6 octahedral moiety. Those host crystals that locate the Mn 4+ ion at a noncentrosymmetric site (absence of inversion symmetry) relax the parity section rule, which enhances the R-line intensity. Increased R-line intensity in the emission spectrum produces color changes that increases phosphor luminosity. The influence of second coordination sphere (next-nearest neighbors) on the R-line intensity is considered. This article establishes guidelines for the development of host crystals that meet the requirements of high luminosity phosphors for general illumination applications.

36 MATERIALS SCIENCE↗
DOE OSTI2021

In situ study of the electronic structure of polar-to-polar SrTiO 3 /($000\bar1$)ZnO heterointerface

The SrTiO 3 (STO)/ZnO heterointerface, which is widely used in the fabrication of novel optoelectronic devices, is a classical system combining functional perovskite oxides and wurtzite-structure semiconductor materials. The electronic structure of the heterointerface often plays a significant role in controlling the functions of novel devices. In this study, the electronic structure was explored using in situ photoemission spectroscopy and X-ray absorption spectroscopy. X-ray diffraction results showed the coexistence of (111) STO and (011) STO orientations for the STO film deposited on the ZnO-($000\bar1$) substrate via pulsed laser deposition. High-resolution transmission electron microscopic results revealed two types of polar interfaces: [$11\bar2$][$10\bar1$](111) STO //[$1\bar210$][$10\bar10$]($000\bar1$) ZnO and [111][$2\bar1\bar1$](011) STO //[$10\bar21$][$10\bar10$]($000\bar1$)ZnO. In situ photoemission spectroscopic results revealed downward band bending and the transformation of the valence states of Ti from 4+ to 3+, with extra electrons transferring to the hybridization states between O 2p and Ti t 2g orbitals at the polar-to-polar STO/ZnO interface. We propose that the polar discontinuity drives the electron transfer to the STO/ZnO interface during the growth process. This study provides insight into the electronic structure of the STO/($000\bar1$)ZnO heterointerface.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2022

The Impact of Structural Distortions on the Magnetism of Double Perovskites Containing 5d 1 Transition-Metal Ions

Five double perovskites, each containing a transition-metal ion with a 5d 1 configuration, have been studied to better understand the surprising diversity of magnetic ground states seen in these isoelectronic compounds. Ba 2 ZnReO 6 adopts the cubic double perovskite structure and magnetically orders below 16 K, with a canted ferromagnetic structure and a saturated magnetization of ~0.24 μ B /Re. X-ray magnetic circular dichroism indicates a substantial orbital moment of approximately 0.4 μ B /Re that opposes the spin moment. The structures of Ba 2 NaOsO 6 (canted ferromagnet, T C = 7 K) and Ba 2 LiOsO 6 (antiferromagnet, T N = 8 K) are reinvestigated using time-of-flight neutron powder diffraction and found to crystallize with the cubic double perovskite structure. No evidence for a structural distortion can be found in either compound down to 10 K. Ba 2 CdReO 6 is also cubic at room temperature but undergoes a structural transition upon cooling below ~180 K to a tetragonal structure with I4/m symmetry that involves compression of the Re–O bonds that are parallel to the c-axis. Sr 2 LiOsO 6 shows a similar tetragonal distortion at room temperature and maintains that structure down to 10 K. Surprisingly, the Os-centered octahedron in Sr 2 LiOsO 6 is distorted in the opposite direction, exhibiting an elongation of the Os–O bonds along the c-axis. Differences in the distortions of the octahedra lead to different magnetic ground states, antiferromagnetic (T N = 4 K) for Ba 2 CdReO 6 and spin glass (T g = 30 K) for Sr 2 LiOsO 6 . Theoretical modeling shows that the varied magnetic behaviors of double perovskites containing 5d 1 ions are closely tied to crystallographic distortions. Furthermore, these distortions remove the degeneracy of the 5d t 2g orbitals, leading to changes in orbital occupation that ultimately determine which of the several competing magnetic ground states is favored.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Exploring the Links between Structural Distortions, Orbital Ordering, and Multipolar Magnetic Ordering in Double Perovskites Containing Re(VI) and Os(VII)

A combination of high-resolution powder diffraction techniques and solid-state NMR has been employed to explore the links between crystal structure, orbital ordering, and magnetism in three isostructural double perovskites containing transition metal ions with a 5d 1 configuration. In Ba 2 ZnReO 6 , both neutron and synchrotron X-ray powder diffraction data reveal a cubic-to-tetragonal transition at 23 K that breaks the degeneracy of the t 2g orbitals and leads to a pattern of orbital ordering that stabilizes magnetic ordering when the sample is cooled below 16 K. Similar behavior is observed in Ba 2 MgReO 6 , with an orbital ordering temperature of 33 K and a magnetic ordering temperature of 18 K. Prior theoretical works suggest that the pattern of orbital order seen in the P42/mnm space group is needed to stabilize the heavily canted antiferromagnetism of these compounds. Unfortunately, powder diffraction data is not sensitive enough to differentiate between the I4/mmm and P42/mnm structural models, as the distortions are too subtle to be unambiguously identified from either neutron or synchrotron X-ray powder diffraction methods. In contrast, both diffraction and 7 Li NMR data indicate that Ba 2 LiOsO 6 retains the cubic structure down to 1.7 K. The antiferromagnetic ground state and lack of any sign of orbital ordering in Ba 2 LiOsO 6 provide compelling evidence that the electronically driven tetragonal distortion seen in Ba2ZnReO6, and Ba2MgReO6 is intimately linked to the magnetic ordering seen in those compounds. The absence of magnetic reflections in high intensity neutron powder diffraction data collected on Ba 2 MgReO 6 strongly suggests ordering of multipolar moments on Re(VI), likely ferro-octupolar ordering.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

The Crystal Structure and Magnetic Behavior of Quinary Osmate and Ruthenate Double Perovskites La ABB 'O 6 ( A = Ca, Sr; B = Co, Ni; B ' = Ru, Os)

In this work, six LaABB'O 6 (A = Ca, Sr; B = Co, Ni; B' = Ru, Os) double perovskites were synthesized, several for the first time, and their crystal structures and magnetic behavior were characterized with neutron powder diffraction and direct-current and alternating-current magnetometry. All six compounds crystallize with P2 1 /n space group symmetry, resulting from a – a – c + octahedral tilting and complete rock salt ordering of transition-metal ions. Despite the electronic configurations of the transition-metal ions, either d 8 –d 3 or d 7 –d 3 , not one of the six compounds shows ferromagnetism as predicted by the Goodenough–Kanamori rules. LaSrNiOsO 6 , LaSrNiRuO 6 , and LaCaNiRuO 6 display long-range antiferromagnetic order, while LaCaNiOsO 6 , LaCaCoOsO 6 , and LaSrCoOsO 6 exhibit spin-glass behavior. These compounds are compared to the previously studied LaCaCoRuO 6 and LaSrCoRuO 6 , both of which order antiferromagnetically. Lastly, the observed variations in magnetic properties can be attributed largely to the response of competing superexchange pathways due to changes in B–O–B' bond angles, differences in the radial extent of the 4d (B' = Ru) and 5d (B' = Os) orbitals, and filling of the t 2g orbitals of the 3d ion.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Systematic Improvement of Quantum Monte Carlo Calculations in Transition Metal Oxides: sCI-Driven Wavefunction Optimization for Reliable Band Gap Prediction

Accurate determination of the electronic properties of correlated oxides remains a significant challenge for computational theory. Traditional Hubbard-corrected density functional theory (DFT+U) frequently encounters limitations in precisely capturing electron correlation, particularly in predicting band gaps. We introduce a systematic methodology to enhance the accuracy of diffusion Monte Carlo (DMC) simulations for both ground and excited states, focusing on LiCoO 2 as a case study. By employing a selected configuration interaction (sCI) approach, we demonstrate the capability to optimize wavefunctions beyond the constraints of single-reference DFT+U trial wavefunctions. Here, we show that the sCI framework enables accurate prediction of band gaps in LiCoO 2 , closely aligning with experimental values and substantially improving traditional computational methods. The study uncovers a nuanced mixed state of t 2g and e g orbitals at the band edges that is not captured by conventional single-reference methods, further elucidating the limitations of PBE+U in describing d-d excitations. Our findings advocate for the adoption of beyond-DFT methodologies, such as sCI, to capture the essential physics of excited-state wavefunctions in strongly correlated materials. The improved accuracy in band gap predictions and the ability to generate more reliable trial wavefunctions for DMC calculations underscore the potential of this approach for broader applications in the study of correlated oxides. This work not only provides a pathway for more accurate simulations of electronic structures in complex materials but also suggests a framework for future investigations of the excited states of other challenging systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗