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The X-ray emission spectrometer at SPring-8 BL07LSU has recently been upgraded with advanced modifications that enable the rotation of the spectrometer with respect to the scattering angle. This major upgrade allows the scattering angle to be flexibly changed within the range of 45–135°, which considerably simplifies the measurement of angle-resolved X-ray emission spectroscopy. To accomplish the rotation system, a sophisticated sample chamber and a highly precise spectrometer rotation mechanism have been developed. The sample chamber has a specially designed combination of three rotary stages that can smoothly move the connection flange along the wide scattering angle without breaking the vacuum. In addition, the spectrometer is rotated by sliding on a flat metal surface, ensuring exceptionally high accuracy in rotation and eliminating the need for any further adjustments during rotation. A control system that integrates the sample chamber and rotation mechanism to automate the measurement of angle-resolved X-ray emission spectroscopy has also been developed. This automation substantially streamlines the process of measuring angle-resolved spectra, making it far easier than ever before. Furthermore, the upgraded X-ray emission spectrometer can now also be utilized in diffraction experiments, providing even greater versatility to our research capabilities.

Metal-organic frameworks (MOFs) exhibit structural flexibility induced by temperature and guest adsorption, as demonstrated in the structural breathing transition in certain MOFs between narrow-pore and large-pore phases. Soft modes were suggested to entropically drive such pore breathing through enhanced vibrational dynamics at high temperatures. In this work, oxygen K-edge resonant X-ray emission spectroscopy of the MIL-53(Al) MOF was performed to selectively probe the electronic perturbation accompanying pore breathing dynamics at the ligand carboxylate site for metal–ligand interaction. It was observed that the temperature-induced vibrational dynamics involves switching occupancy between antisymmetric and symmetric configurations of the carboxylate oxygen lone pair orbitals, through which electron density around carboxylate oxygen sites is redistributed and metal–ligand interactions are tuned. In turn, water adsorption involves an additional perturbation of π orbitals not observed in the structural change solely induced by temperature.

Carbon Fiber Reinforced Plastic (CFRP) is a composite material consisting of a resin matrix and carbon fiber reinforcement. The material is also commonly used in a prepreg laminate, a unidirectional reinforcing material with high strength and stiffness in one direction. Damage to laminates is highly complex, including delamination, fiber fracture, and base matrix cracking, requiring highly efficient and accurate non-destructive testing. Infrared stress measurement is an example of a non-destructive testing method for CFRP structures. The infrared stress measurement is based on Kelvin’s theory to convert the surface temperature fluctuation under cyclic loading to the distributions of sum of principal stress on surface (DSPSS), so it may result in a stress distribution that differs from the actual distribution due to transient heat conduction. It is necessary to consider structural analysis and transient heat conduction in the numerical analysis to reproduce DSPSS obtained by infrared stress measurement. This study performs a finite element analysis with transient heat conduction on simple shaped CFRP specimens to reproduce the trend of DSPSS obtained by infrared stress measurement. Firstly, DSPSS generated by the forced displacement of a CFRP specimen is converted to a temperature distribution using Kelvin’s thermoelastic theory. Finally, a transient heat conduction analysis is performed, and the distribution trend is discussed using the obtained temperature distribution as the initial value. A sheet of Teflon is inserted into the CFRP specimen as a defect, assuming foreign matter contamination during the manufacturing process. Previous study predicts the internal defect information by a machine learning model using the DSPSS from numerical analysis. There is a potential for a high-accuracy defect prediction using DSPSS obtained by the infrared stress measurement if DSPSS obtained by the infrared stress measurement and the numerical analysis have similar tendencies.

Abstract Lithium-ion deintercalation/intercalation during charge/discharge processes is one of the essential reactions that occur in the layered cathodes of lithium-ion batteries, and the performance of the cathode can be expressed as the sum of the reactions that occur in the local area of the individual cathode particles. In this study, the spatial distributions of the chemical states present in prototypical layered LiCoO2 cathode particles were determined at different charging conditions using scanning transmission X-ray microscopy (STXM) with a spatial resolution of approximately 100 nm. The Co L 3- and O K-edge X-ray absorption spectroscopy (XAS) spectra, extracted from the same area of the corresponding STXM images, at the initial state as well as after charging to 4.5 V demonstrate the spatial distribution of the chemical state changes depending on individual particles. In addition to the Co L 3-edge XAS spectra, the O K-edge XAS spectra of the initial and charged LiCoO2 particles are different, indicating that both the Co and O sites participate in charge compensation during the charging process possibly through the hybridization between the Co 3d and O 2p orbitals. Furthermore, the element maps of both the Co and O sites, derived from the STXM stack images, reveal the spatial distribution of the chemical states inside individual particles after charging to 4.5 V. The element mapping analysis suggests that inhomogeneous reactions occur on the active particles and confirm the existence of non-active particles. The results of this study demonstrate that an STXM-based spatially resolved electronic structural analysis method is useful for understanding the charging and discharging of battery materials.

We study high harmonic generation (HHG) in the visible spectral range generated in a flat liquid jet of H _2 O, excited by intense mid-infrared (MIR) radiation around 3 μm, which is nearly resonant with the OH vibrational modes. By introducing a weak excitation pulse prior to the intense MIR driver pulse for HHG, we observed an enhancement of the 5th, 7th, and 9th harmonics occurring approximately 2 ps after excitation and persisting for more than 120 ps, which is completely absent in the case of non-resonant D _2 O. These results suggest that the enhancement is caused by ultrafast heating through vibrational excitation.

Abstract An X-ray is the well-known probe to examine structure of materials, including our own bodies. The X-ray beam, especially at the wavelength of nanometers, has also become significant to directly investigate electronic states of a sample. Such an X-ray is called a soft X-ray and polarization dependence of the light-matter interaction further unveils the microscopic properties, such as orbitals or spins of electrons. Generation of high brilliant beams of the polarized X-ray has linked to development of our experimental science, and it has been made by radiation from relativistic electrons at the synchrotron radiation facilities over the world. Recently, we constructed a new polarization-controlled X-ray source, the segmented cross undulator, at SPring-8, the largest synchrotron radiation facility in the world. The operation is based on interference of X-ray beams, which is sharply contrast to the conventional method of regulating electron trajectory by the mechanical control of magnets. The paradigm shift opened the measurement innovations and allowed us to design new experimental approaches to capture signals that have been hidden in materials. The present review describes the novel X-ray source with the principle of operation and the technical details of optimization. Examples of the frontier spectroscopies that use unique optical properties of the source are introduced, followed by the future prospects for next generation synchrotron radiation facilities.

Abstract Purpose The aim of the present study was to investigate the effect of glutathione ethyl ester (GSH‐OEt) in the recovery medium on the developmental competence of mouse vitrified‐warmed MII oocytes. Methods Vitrified‐warmed oocytes were incubated for 1 h in recovery medium in the presence or absence of 0.5 mM GSH‐OEt. The authors examined the effects of GSH‐OEt, first on the levels of glutathione (GSH) and reactive oxygen species (ROS) in vitrified‐warmed oocytes, and second, on in vitro blastocyst development, division speed to blastocysts, and total cell numbers of blastocysts from vitrified‐warmed oocytes fertilized by Intracytoplasmic sperm injection (ICSI). Results Adding GSH‐OEt to the recovery medium significantly (p

Background: Luteal phase support (LPS) is essential for hormone replacement therapy (HRT) for frozen-thawedembryo transfer (FET). However, the optimal dose and serum progesterone (P4) levels required for pregnancy arecontroversial. We attempted to determine the association between pregnancy outcomes and serum P4 levels administeredvia vaginal suppository for HRT-FET cycles on embryo transfer day.Materials and Methods: This was a secondary analysis of the dataset from the EXCULL trial, which prospectivelyinvestigated pregnancy outcomes of four different P4 vaginal suppositories (Lutinus, Utrogestan, Luteum, andCrinone) for HRT-FET. It was conducted at a private fertility clinic between December 2016 to December 2017.During this trial, 235 cycles were divided into four groups based on serum P4 values (quartile [Q] 1 group: 13.7 ng/mL). We investigated clinicalpregnancy rate (CPR), positive fetal heart rate (FHR), live birth rate (LBR), and miscarriage rate (MR) for eachgroup. A logistic regression analysis was performed using age, body mass index (BMI), and transferred embryosas covariates.Results: Serum P4 values (ng/mL) of each drug were as follows: Lutinus, 13.3 ± 4.9; Utrogestan, 9.3 ± 3.3; Luteum,13.6 ± 4.2; and Crinone, 8.7 ± 3.2 (mean ± standard deviation, p

Abstract Purpose To investigate the first‐division kinetics and in vitro development of embryos produced by injecting sonicated sperm heads with high or low chromosomal integrity into oocytes. Methods Mouse spermatozoa were frozen after separating the sperm heads from the tails by sonication in an EGTA solution (EGTA group) or M2 medium (M2 group). The chromosomal integrity of sonicated mouse spermatozoa was analyzed by injecting the sperm heads into fresh mouse oocytes. The developmental potential of spermatozoa was examined by injecting the sperm heads into vitrified‐warming mouse oocytes. We used a time‐lapse monitoring system to compare the first‐division kinetics. Results Chromosomal integrity was preserved significantly more frequently in the EGTA group (90.6%) than in the M2 group (32.7%). Blastocysts developed significantly more often in the EGTA group (80.8%) than in the M2 group (39.6%). In the M2 group, with frequent chromosome aberrations, the time between the sperm injection and first cleavage was delayed (18.4 hours), compared to the EGTA group (16.5 hours). All results of the EGTA group were similar to that of fresh epididymal spermatozoa. Conclusion The EGTA solution for sonication maintained the integrity of sperm chromosomes. Our results revealed a relationship between sperm chromosome integrity and first‐division kinetics.

Constant strain rate nanoindentation testing is useful for evaluating local strain rate sensitivity. In titanium alloys, the dwell fatigue at room temperature is a critical issue, and this phenomenon is known as relating to local strain rate sensitivity. We investigate the local strain rate sensitivity of Ti–6242S and IMI834 which are well known heat resistant titanium alloys. Firstly, the validity of strain rate sensitivity by using dynamic nanoindentation testing was verified by measuring the material which has low strain rate sensitivity. Then, rate sensitivity of titanium alloy was examined by nanoindentation testing. Combined with the results from the structural analysis by the electron back scattered diffraction pattern, the factors which affect the strain rate sensitivity are investigated.

Hydrogen-bonded network of water surrounding polymers is expected to be one of the most relevant factors affecting biocompatibility, while the specific hydrogen-bonded structure of water responsible for biocompatibility is still under debate. Here we study the hydrogen-bonded structure of water in a loop-shaped poly(ethylene glycol) chain in a polyrotaxane using synchrotron soft X-ray emission spectroscopy. By changing the density of anchoring molecules, hydrogen-bonded structure of water confined in the poly(ethylene glycol) loop was identified. The XES profile of the confined water indicates the absence of the low energy lone-pair peak, probably because the limited space of the polymer loop entropically inhibits the formation of tetrahedrally coordinated water. The volume of the confined water can be changed by the anchoring density, which implies the ability to control the biocompatibility of loop-shaped polymers.

Abstract Purpose The time‐lapse system is a device that allows continuous monitoring without removing embryos from the incubator. Using a time‐lapse system, we retrospectively investigated cleavage speed time points as potential indicators for selecting high‐quality viable blastocysts. Methods This study included 963 zygotes of two pronuclei retrieved from 196 patients between January 2015 and December 2016. All embryos in culture were monitored by time‐lapse after intracytoplasmic sperm injection. Of 492 blastocysts developed in vitro, 128 vitrified‐warmed single blastocyst transfers were classified into pregnancy and non‐pregnancy groups, and the parameters were compared. Results In the pregnancy group, timing of both morula compaction and regular blastocyst formation was significantly faster than in the non‐pregnancy group. Furthermore, the optimal cutoff values for compacted morula (94.9 hours) and regular blastocyst (113.9 hours) were determined using the receiver operator characteristic curve analysis. Embryos that formed compacted morulae within 94.9 hours and developed into regular blastocysts within 113.9 hours were associated with a significantly higher pregnancy rate than those that did not (44.4% vs 16.0%). Conclusion The timing of morula compaction and regular blastocyst formation is important as an indicator of high‐quality blastocysts to increase odds for pregnancy after embryo transfer.

Abstract In situ high energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD-XAS) was used to systematically evaluate interactions of H2O and O2 adsorbed on Pt and Pt3Co nanoparticle catalysts in different particle sizes. The systematic increase in oxidation due to adsorption of different species (H2O adsorption

Sodium-excess metal oxides Na2MO3 are appealing cathode materials for sodium-ion batteries. Here, the authors demonstrate that honeycomb-type cation ordering in Na2RuO3 triggers the oxygen redox reaction via frontier orbital reorganization, increasing the capacity by 1/3 compared with disordered Na2RuO3.

Metal-organic frameworks (MOFs) exhibit structural flexibility induced by temperature and guest adsorption, as demonstrated in the structural breathing transition in certain MOFs between narrow-pore and large-pore phases. Soft modes were suggested to entropically drive such pore breathing through enhanced vibrational dynamics at high temperatures. In this work, oxygen K-edge resonant X-ray emission spectroscopy of the MIL-53(Al) MOF was performed to selectively probe the electronic perturbation accompanying pore breathing dynamics at the ligand carboxyl­ate site for metal-ligand interaction. It was observed that the temperature-induced vibrational dynamics involves switching occupancy between antisymmetric and symmetric configurations of the carboxylate oxygen lone pair orbitals, through which electron density around carboxylate oxygen sites is redistributed and metal-ligand interactions are tuned. In turn, water adsorption involves an additional perturbation of π orbitals not observed in the structural change solely induced by temperature. [ABSTRACT FROM AUTHOR]

The hot deformation behavior of a Mg-14-Li-6A-l1Ca alloy was studied using the hot compression true stressstrain curves corresponding to the temperature range of 473673K at strain rates of 1 × 10-1-1 × 10 3 s 1. The true stressstrain curves indicated dynamic softening under the test conditions. The peak stress during deformation could be correlated with the temperature and strain rate using a hyperbolic-sine equation. The activation energy of the Mg14Li6Al1Ca alloy was determined to be 193 kJ mol-1. The Zener-Hollomon parameter (Z) for the Mg14Li6Al1Ca alloy was determined. The tendency for dynamic recrystallization increases at low strain rates and high temperatures, corresponding to low Z values. The hot deformation behavior of the Mg-14-Li-6A-l1Ca alloy was modelled by a suitable constitutive equation. Furthermore, the size of the equiaxed grains in the hot-deformed and quenched specimens was estimated from the Z value. [ABSTRACT FROM AUTHOR]

N 1s X-ray absorption, X-ray photoemission and resonant X-ray emission spectroscopy are used to investigate the electronic structures of a series of DNA nucleobases and their dinucleotides. Results indicate the guanine base and its nucleotide have a weak structure at the lowest binding energy and at this energy they isolate from the main valence band and form the highest occupied molecular orbital state.

The role of transition metals in chemical reactions is often derived from probing the metal 3d states. However, the relation between metal site geometry and 3d electronic states, arising from multielectronic effects, makes the spectral data interpretation and modeling of these optical excited states a challenge. Here we show, using the well-known case of red ruby, that unique insights into the density of transition metal 3d excited states can be gained with 2p3d resonant inelastic X-ray scattering (RIXS). We compare the experimental determination of the 3d excited states of Cr3+ impurities in Al2O3 with 190 meV resolution 2p3d RIXS to optical absorption spectroscopy and to simulations. Using the crystal field multiplet theory, we calculate jointly for the first time the Cr3+ multielectronic states, RIXS, and optical spectra based on a unique set of parameters. We demonstrate that (i) anisotropic 3d multielectronic interactions causes different scaling of Slater integrals, and (ii) a previously not observed doublet excited state exists around 3.35 eV. These results allow to discuss the influence of interferences in the RIXS intermediate state, of core-hole lifetime broadenings, and of selection rules on the RIXS intensities. Finally, our results demonstrate that using an intermediate excitation energy between L3 and L2 edges allows measurement of the density of 3d excited states as a fingerprint of the metal local structure. This opens up a new direction to pump-before-destroy investigations of transition metal complex structures and reaction mechanisms. [ABSTRACT FROM AUTHOR]

We report damage in trenches produced by laser irradiation of a carbon fiber reinforced plastic (CFRP) plate. Laser cutting of CFRP was performed by multi-pass irradiation with a continuouswave fiber IR laser (multi-mode laser, average power: 3.3 kW). The damaged sidewall of the trench in the samples was analyzed by microscopic X-ray computed tomography. Low-speed laser scanning with a galvanometer scanner significantly damaged the sidewall surface and created a wide heat-affected zone. As the thickness of the damaged area was correlated with the scanning speed of the laser beam, the damaged region length was analyzed using the heat penetration depth equation. [ABSTRACT FROM AUTHOR]

We report deep-trench microstructures fabricated on carbon-fiber-reinforced thermoplastic (CFRTP; a CFRP containing thermoplastic resin). Well-defined laser cutting free of debris around the trench was achieved for various types of CFRTP plates by single-mode laser irradiation with a fast beam galvanometer scanner using a multiple-scan-pass method. The microfabrication of a CFRTP containing pitch-type carbon fibers and a polycarbonate resin, performed by 600-scan-pass irradiation with a cw kilowatt single-mode IR fiber laser (average power: 1 kW), yielded a trench microstructure with a depth of 18.2 mm and an opening width of 0.32 mm. The laser-induced damage in the samples was analyzed by microscopic X-ray computed tomography. Laser cutting by high-speed beam scanning resulted in a clean top and excellent sidewall quality, along with a negligible heataffected zone. [ABSTRACT FROM AUTHOR]

Here we present an overview of recent developments of X-ray and electron spectroscopy to probe water at different temperatures. Photon-induced ionization followed by detection of electrons from either the O 1s level or the valence band is the basis of photoelectron spectroscopy. Excitation between the O 1s and the unoccupied states or occupied states is utilized in X-ray absorption and X-ray emission spectroscopies. These techniques probe the electronic structure of the liquid phase and show sensitivity to the local hydrogen-bonding structure. Both experimental aspects related to the measurements and theoretical simulations to assist in the interpretation are discussed in detail. Different model systems are presented such as the different bulk phases of ice and various adsorbed monolayer structures on metal surfaces. [ABSTRACT FROM AUTHOR]

We report here laser cutting of carbon fiber reinforced plastic (CFRP) with an IR fiber laser (average power: 2 - 3 kW). The CFRP samples contain thermoplastic resin (CFRTP; carbon fiber reinforced thermo-plastic) or thermosetting resin as binding plastic. Well-defined laser cutting free of debris around the groove was performed for various type of CFRP plates by the laser irradiation with a fast beam galvanometer scanner on a multiple-scan-pass method. The laser-induced damage in the samples was observed and analyzed by microscopic X-ray Computed Tomography. Laser cutting with a high speed beam scanning exhibits a clean top and excellent sidewall quality along with a negligible heat-affected zone. [ABSTRACT FROM AUTHOR]

We report on the laser cutting of carbon fiber reinforced thermo-plastic (CFRTP) with a cw IR fiber laser (average power: 1 kW). CFRTP is a composite material which contains carbon fibers and binding thermoplastic. A well-defined cutting of CFRTP which was free of debris around the groove was performed by the laser irradiation with a fast beam galvanometer scanning on a multiple-scan-pass method. The area of laser-induced damages in the samples was observed by microscopic X-ray Computed Tomography and micro- Raman spectroscopy. Laser cutting with a high speed beam scanning exhibits a clean top and an excellent sidewall quality along with a negligible heat affected zone. [ABSTRACT FROM AUTHOR]

A new soft X-ray beamline, BL07LSU, has been constructed at SPring-8 to perform advanced soft X-ray spectroscopy for materials science. The beamline is designed to achieve high energy resolution (E/ΔE> 10000) and high photon flux [>1012 photons s-1 (0.01% bandwidth)-1] in the photon energy range 250-2000 eV with controllable polarization. To realise this state-of-the-art performance, a novel segmented cross undulator was developed and adopted as a light source. The details of the undulator light source and beamline monochromator design are described. The achieved performance of the beamline, such as the photon flux, energy resolution and the state of polarization, is reported. [ABSTRACT FROM AUTHOR]

High-resolution O 1 s resonant inelastic x-ray scattering spectra of liquid H2O, D2O, and HDO, obtained by excitation near the preedge resonance show, in the elastic line region, well-separated multiple vibrational structures corresponding to the internal OH stretch vibration in the ground state of water. The energy of the first-order vibrational excitation is strongly blueshifted with respect to the main band in the infrared or Raman spectra of water, indicating that water molecules with a highly weakened or broken donating hydrogen bond are correlated with the preedge structure in the x-ray absorption spectrum. The vibrational profile of preedge excited HDO water is well fitted with 50% ± 20% greater OH-stretch contribution compared to OD, which strongly supports a preference for OH being the weakened or broken H-bond in agreement with the well-known picture that D2O makes stronger H-bonds than H2O. Accompanying path-integral molecular dynamics simulations show that this is particularly the case for strongly asymmetrically H-bonded molecules, i.e., those that are selected by preedge excitation. [ABSTRACT FROM AUTHOR]

Multi-phonon excitations, indicating a strong electron-phonon coupling, were observed by soft X-ray resonant inelastic X-ray scattering of Mg2FeH6 and Mg2FeD6. The Fe-H/D stretch and bend modes are selectively activated by the tuned electron excitation to eg brach of Fe 3d states in octahedral symmetry. The energy deviation with the factor of ∼√2 due to the isotope effect was clearly observed. [ABSTRACT FROM AUTHOR]

(Ga,Mn)As is a paradigm of a diluted magnetic semiconductor which shows ferromagnetism induced by doped hole carriers. With a few controversial models emerging from numerous experimental and theoretical studies, the mechanism of the ferromagnetism in (Ga,Mn)As still remains a puzzling enigma. In this article, we use soft x-ray angle-resolved photoemission spectroscopy to positively identify the ferromagnetic Mn 3d-derived impurity band (IB) in (Ga,Mn)As. The band appears dispersionless and hybridized with the light-hole band of the host GaAs. These findings conclude the picture of the valence-band structure of (Ga,Mn)As disputed for more than a decade. The nondispersive character of the IB and its location in vicinity of the valence-band maximum indicate that the Mn 3d-derived IB is formed as a split-off Mn-impurity state predicted by the Anderson impurity model. Responsible for the ferromagnetism is predominantly the transport of hole carriers in the IB. [ABSTRACT FROM AUTHOR]

Fe L2,3-edge x-ray absorption spectra (XAS) and magnetic circular dichroism (MCD) in resonant inelastic x-ray scattering (RIXS) of α-Fe2O3 were measured to identify the electronic structure responsible for its weak ferromagnetism caused by the Dzyaloshinskii-Moriya interaction (DMI) at room temperature. In contrast to negligible MCD in XAS, MCD in RIXS (RIXS-MCD) was clearly observed in the dd excitation at 1.8 eV via excitation to charge-transfer states. Furthermore, RIXS-MCD showed a crystal orientation dependence, indicating that the observed RIXS-MCD originated from DMI. The observed RIXS-MCD is well described by ab initio charge-transfer multiplet calculations, revealing that the RIXS-MCD derives from spin flip excitations at delocalized eg orbitals. By the combination of the experiments and calculations, RIXS-MCD has unraveled that the origin of DMI in α-Fe2O3 is the eg orbitals, which are strongly hybridized with the 2p orbitals of oxygen atoms. The results demonstrate the importance of RIXS-MCD for identifying the electronic structure related to DMI. [ABSTRACT FROM AUTHOR]

We investigate electronic excitations in La2-x(Br,Sr)xCuO4 using resonant inelastic x-ray scattering (RIXS) at the oxygen K edge. RIXS spectra of the hole-doped cuprates show clear momentum dependence below 1 eV. The broad spectral weight exhibits positive dispersion and shifts to higher energy with increasing hole concentration. Theoretical calculation of the dynamical charge structure factor on oxygen orbitals in a three-band Hubbard model is consistent with the experimental observation of the momentum and doping dependence, and therefore the momentum-dependent spectral weight is ascribed to intraband charge excitations which have been observed in electron-doped cuprates. Our results confirm that the momentum-dependent charge excitations exist on the order of the transfer energy (t), and the broad spectral line shape indicates damped and incoherent character of the charge excitations at the energy range in the doped Mott insulators. [ABSTRACT FROM AUTHOR]

Nuclear quantum effects (NQEs) have a significant influence on the hydrogen bonds in water and aqueous solutions and have thus been the topic of extensive studies. However, the microscopic origin and the corresponding temperature dependence of NQEs have been elusive and still remain the subject of ongoing discussion. Previous x-ray scattering investigations indicate that NQEs on the structure of water exhibit significant temperature dependence [Phys. Rev. Lett. 94, 047801 (2005)]. Here, by performing wide-angle x-ray scattering of H2O and D2O droplets at temperatures from 275 K down to 240 K, we determine the temperature dependence of NQEs on the structure of water down to the deeply supercooled regime. The data reveal that the magnitude of NQEs on the structure of water is temperature independent, as the structure factor of D2O is similar to H2O if the temperature is shifted by a constant 5 K, valid from ambient conditions to the deeply supercooled regime. Analysis of the accelerated growth of tetrahedral structures in supercooled H2O and D2O also shows similar behavior with a clear 5 K shift. The results indicate a constant compensation between NQEs delocalizing the proton in the librational motion away from the bond and in the OH stretch vibrational modes along the bond. This is consistent with the fact that only the vibrational ground state is populated at ambient and supercooled conditions. [ABSTRACT FROM AUTHOR]