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THz/Far Infrared synchrotron absorption experiments on pure and doped MgB2 samples show that the absorption spectral weight at low wavenumber (i.e.

The electrochemical energy storage of lithium and sodium ions from aqueous solutions in binary metal oxides is of great interest for renewable energy storage applications. Binary metal oxides are of interest for aqueous energy storage due to their better structural stability and electronic conductivity and tunability of redox potentials. They have also been widely studied as novel electrodes for supercapacitors. The interactions between water and lithium/sodium ions, and water and binary metal oxide surface determine the electrochemical reactions and their long-term stability. Our results indicate that the aqueous sodium electrolyte has a stronger influence on the capacitance and cycling stability of the binary (Ca and Mo) metal oxide electrode than its lithium cousin. The symmetric cell in a two-electrode configuration was assembled with the proposed binary metal oxide, which shows an average discharge voltage of 1.2 V, delivering a specific capacitance of 72 F g−1 at a specific energy density of 32 W h kg−1 based on the total mass of the active materials. The development of highly concentrated aqueous electrolytes such as the “water-in-salt” electrolyte showed a larger electrochemical (voltage) window with enhanced storage capacitance for increasing the salt concentrations has also been discussed.

The melting behaviour of metal-organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through melt-quenching of the cobalt-based zeolitic imidazolate framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co-Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device assembly.

Lead halide perovskite (LHP) semiconductors show exceptional optoelectronic properties. Barriers for their applications, however, lie in their polymorphism, instability to polar solvents, phase segregation, and susceptibility to the leaching of lead ions. We report a family of scalable composites fabricated through liquid-phase sintering of LHPs and metal-organic framework glasses. The glass acts as a matrix for LHPs, effectively stabilizing nonequilibrium perovskite phases through interfacial interactions. These interactions also passivate LHP surface defects and impart bright, narrow-band photoluminescence with a wide gamut for creating white light-emitting diodes (LEDs). The processable composites show high stability against immersion in water and organic solvents as well as exposure to heat, light, air, and ambient humidity. These properties, together with their lead self-sequestration capability, can enable breakthrough applications for LHPs.

Capabilities of the Attenuated Total Reflection (ATR) at THz wavelengths for increased sub-surface depth characterisation of (bio-)materials is presented. The penetration depth of a THz evanescent wave in biological samples is dependent on the wavelength and temperature and can reach 0.1-0.5 mm depth due to strong refractive index change ∼0.4 of the ice-water transition; this is quite significant and important when studying biological samples. Technical challenges are discussed when using ATR for uneven, heterogeneous, high refractive index samples with possibility of frustrated total internal reflection (a breakdown of the ATR reflection-mode into transmission-mode). Local field enhancements at the interface are discussed with numerical/analytical examples. Maxwell’s scaling was used to model behaviour of absorber-scatterer inside materials at the interface with ATR prism for realistic complex refractive indices of bio-materials. Modality of ATR with polarisation analysis is proposed and its principle illustrated, opening an invitation for its experimental validation. The sensitivity of the polarised ATR mode to the refractive index between the sample and ATR prism is revealed. Design principles of polarisation active optical elements and spectral filters are outlined. The results and concepts are based on experiments carried out at the THz beamline of the Australian Synchrotron.

Applications of far infrared (Far-IR) and terahertz (THz) radiation in areas such as healthcare and security are fast-growing. As a consequence, humans and the environment are becoming more exposed to mm-wave and Far-IR radiation than previously. We examined typical skin-care and sunscreen ingredients and propitiatory products with transmission FTIR, ATR-FTIR and THz-time domain spectroscopy (THz-TDS) methods using fresh and dehydrated toad and fresh human skin samples for their absorption properties in these frequency ranges. The skin hydration compounds glycerol and sorbitol have comparable absorption characteristics to physiological bulk water. Products containing these and similar hydrating compounds have significant Far-IR absorption characteristics. The sunscreen ingredients ZnO (20 micron), TiO2 (mesh 325), and graphene platelet demonstrate a generally poor Far-IR absorbance, with TiO2 displaying some frequency-specific absorption in the 3-6 THz and 12 THz regions. The Far-IR absorbance of proprietary sunscreens was, however, shown not to be significant. The absorption properties of melanin, collagen, bound water, and other constituents are significant in dehydrated skin samples but are not of the same order of importance as the hydrating agents examined.

A novel method of investigating the temperature dependent variation of aspects of the complex refractive index n* in samples in the THz range using continuous, non-polarised, synchrotron radiation is presented. The method relies on the use of ATR apparatus, and retains the advantage of minimal sample preparation, which is a feature of ATR techniques. The method demonstrates a “proof of concept” of monitoring temperature reflectance whilst continuously heating or cooling samples by using a temperature variable Thermal Sample Stage. The method remains useful when the refractive index of the sample precludes attenuated total reflection study. This is demonstrated with the water reflectance experiments. The temperature dependent ATR reflectance of tissue-representative fats (lard and Lurpak® butter) was investigated with the novel approach. Both are within the ATR range of the diamond crystal in a “true” ATR mode. Lard showed no clear temperature variation between −15 °C and 24 °C at 0.7 to 1.15 THz or 1.70 to 2.25 THz. Lard can be regarded as having invariable, constant, dielectric properties within mixtures when biological substances are being assessed for temperature dependent dielectric variation within the stated THz ranges. Lurpak® butter (water content 14.7%) displayed temperature dependent reflected signal intensity features with a steady decline in reflectivity with increasing temperature. This is in line with the temperature-dependent behaviour of liquid water. There is no rapid change in reflected signal intensity even at −20 °C, suggesting that emulsified water retains liquid-water-like THz properties at freezing temperatures.

Recently, it was demonstrated that Terahertz (THz) radiation facilitates elongation of tubulin microtubules and actin microfilaments. The phenomenon could have a dramatic impact on living cells, especially in the phase of cell development when dramatic structural changes in cytoskeleton occur. In this study, the THz/Far-IR Beamline of Australian Synchrotron was used as a broadband source of THz radiation to stimulate perturbation in cytoskeleton structure in neuronal culture. Preliminary results indicate alterations of neurite shape and length in THz exposed cell cultures.

Acetonitrile (CH3CN) and water (H2O) ice particles were generated within a collisional cooling cell coupled to the Australian Synchrotron light source. The evolution of the aerosols was tracked by infrared spectroscopy compiled over the 4000–50 cm–1 region. Gas pressure and temperature conditions were varied to replicate the lower altitudes of the Titan atmosphere allowing for comparison to far-infrared features detected by the Cassini–Huygens spacecraft. The experimental spectra show that CH3CN and H2O particles are microheterogeneous in composition and spherical in shape. CH3CN lattice bands display temperature-dependent shifts in frequency, implying that pure β-phase is present in the mixed particles. In addition, a red shift identified for the C≡N fundamental stretching mode indicates dipole–dipole and π-electron side-directed hydrogen bond coupling between segregated CH3CN and H2O phases exclusively at the grain interface. Discrete dipole approximation theory was implemented to evaluate various clust...

Observations of the torsional and low-lying vibrational–torsional states of toluene, p-fluorotoluene, and m-fluorotoluene using the technique of two dimensional laser induced fluorescence (2D-LIF) have revealed interactions between the methyl torsion and low frequency out-of-plane methyl wagging vibration. These interactions can change the values of constants extracted from the analysis of rotational spectra, which usually assume that the large amplitude torsional motion can be treated independent of the small amplitude vibrations. Since out-of-plane methyl wagging modes will be present whenever a methyl group is attached to a planar frame, this type of torsion–vibration interaction is potentially widespread; it is thus important to establish the extent and strength of this type of interaction. 2D-LIF is limited to molecules that fluoresce from excited electronic states, and to explore interactions between torsion and methyl wagging vibrations in a wide range of molecules necessitates developing alternative experimental approaches. Infrared absorption spectroscopy is one such approach. It is shown that for the low torsional barrier case, the torsional sequence bands accompanying the out-of-plane methyl wagging transition provide a sensitive probe of the interaction. As an illustration, the far infrared absorption spectrum of toluene in the region of the M20 band (∼205 cm−1) is presented and analyzed. The torsional sequence structure provides insight into the higher torsional states (up to m = 7) in the ground vibrational state and M20. An analysis of these bands enables the torsion–vibration coupling and torsional constants to be extracted. A general method to analyze such spectra is presented.

Capabilities of the attenuated total reflection (ATR) at THz wavelengths for increased sub-surface depth characterisation of (bio-)materials are presented. The penetration depth of a THz evanescent wave in biological samples is dependent on the wavelength and temperature and can reach 0.1–0.5 mm depth, due to the strong refractive index change ∼0.4 of the ice-water transition; this is quite significant and important when studying biological samples. Technical challenges are discussed when using ATR for uneven, heterogeneous, high refractive index samples with the possibility of frustrated total internal reflection (a breakdown of the ATR reflection mode into transmission mode). Local field enhancements at the interface are discussed with numerical/analytical examples. Maxwell’s scaling is used to model the behaviour of absorber–scatterer inside the materials at the interface with the ATR prism for realistic complex refractive indices of bio-materials. The modality of ATR with a polarisation analysis is proposed, and its principle is illustrated, opening an invitation for its experimental validation. The sensitivity of the polarised ATR mode to the refractive index between the sample and ATR prism is numerically modelled and experimentally verified for background (air) spectra. The design principles of polarisation active optical elements and spectral filters are outlined. The results and proposed concepts are based on experimental conditions at the THz beamline of the Australian Synchrotron.

Here we reveal details of the interaction between human lysozyme proteins, both native and fibrils, and their water environment by intense terahertz time domain spectroscopy. With the aid of a rigorous dielectric model, we determine the amplitude and phase of the oscillating dipole induced by the THz field in the volume containing the protein and its hydration water. At low concentrations, the amplitude of this induced dipolar response decreases with increasing concentration. Beyond a certain threshold, marking the onset of the interactions between the extended hydration shells, the amplitude remains fixed but the phase of the induced dipolar response, which is initially in phase with the applied THz field, begins to change. The changes observed in the THz response reveal protein-protein interactions me-diated by extended hydration layers, which may control fibril formation and may have an important role in chemical recognition phenomena.

A focal plane array (FPA) detector was used for hyperspectral imaging in the infrared (IR) spectral region using thermal and synchrotron light sources. FPA Fourier-transform IR (FTIR) imaging microspectroscopy will be able to monitor real time changes at specific absorption bands when combined with high brightness synchrotron source. In this study, several types of samples with unique structural motifs were selected and used for assessing the capability of the FPA-FTIR imaging technique. It was shown that the time required for polariscopy at IR wavelengths can be substantially reduced by the FPA-FTIR imaging approach. By using natural and laser fabricated polymers with sub-wavelength features, alignment of absorbing molecular dipoles was revealed as well as higher order patterns (laser fabricated structures). Micro-spectroscopy of absorber orientation reveals alignment patterns even when they are not spatially resolved.

High frequency (HF) electromagnetic fields (EMFs) have been widely used in many wireless communication devices, yet within the terahertz (THz) range, their effects on biological systems are poorly understood. In this study, electromagnetic radiation in the range of 0.3&ndash, 19.5 &times, 1012 Hz, generated using a synchrotron light source, was used to investigate the response of PC 12 neuron-like pheochromocytoma cells to THz irradiation. The PC 12 cells remained viable and physiologically healthy, as confirmed by a panel of biological assays, however, exposure to THz radiation for 10 min at 25.2 &plusmn, 0.4 &deg, C was sufficient to induce a temporary increase in their cell membrane permeability. High-resolution transmission electron microscopy (TEM) confirmed cell membrane permeabilization via visualisation of the translocation of silica nanospheres (d = 23.5 &plusmn, 0.2 nm) and their clusters (d = 63 nm) into the PC 12 cells. Analysis of scanning electron microscopy (SEM) micrographs revealed the formation of atypically large (up to 1 &micro, m) blebs on the surface of PC 12 cells when exposed to THz radiation. Long-term analysis showed no substantial differences in metabolic activity between the PC 12 cells exposed to THz radiation and untreated cells, however, a higher population of the THz-treated PC 12 cells responded to the nerve growth factor (NGF) by extending longer neurites (up to 0&ndash, 20 &micro, m) compared to the untreated PC12 cells (up to 20 &micro, m). These findings present implications for the development of nanoparticle-mediated drug delivery and gene therapy strategies since THz irradiation can promote nanoparticle uptake by cells without causing apoptosis, necrosis or physiological damage, as well as provide a deeper fundamental insight into the biological effects of environmental exposure of cells to electromagnetic radiation of super high frequencies.

The penetration depth of an evanescent wave in Attenuated Total Reflection (ATR) is dependent on the wavelength of the radiation utilised. At THz frequencies, the penetration depth into biological tissues is in the order of 0.1 to 0.5 mm, rendered pig lard was used as a model sample in this study. A method for the direct measurement of the evanescent wave penetration depth is presented which allows for the estimation of the dispersion of the complex refractive index by using the reflection of the evanescent wave from varying sample depths. The method employs frustrated total internal reflection, and has been demonstrated by using the THz/Far-IR beamline at the Australian synchrotron, and modelled using finite difference time domain (FDTD) simulations.

This combined laboratory and theoretical investigation focussed on a suite of crystalline phenethylamine-class molecules of forensic interest: amphetamine sulfate, levo- and dextro-methamphetamine hydrochloride, 3,4-methyl​enedioxy-methamphetamine (MDMA) hydrochloride, 3,4-methylenedioxy-​amphetamine (MDA) hydrochloride, and the hydrochloride salts of two substituted (4-fluoro and 4-methyl) methcathinones. Far-infrared (far-IR) spectra across the 30–600 cm−1 wavenumber range were recorded at the Australian Synchrotron light source. Resolved absorption profiles enabled vibrational features to be assigned via comparison to periodic density functional theory (p-DFT) performed at the B3LYP-D3/6-311 G(d) level. The calculations accurately reproduce the experimental spectra (frequencies and peak intensities) for ordered molecular crystal-type samples, such as methamphetamine stereoisomers and two substituted methcathinones. Significant band broadening for amphetamine sulfate was observed, likely due to crystal disorder, while MDMA and MDA showed convolved stretching modes from comparatively impure samples. For all seven molecular crystals investigated, previously unpublished peak assignments and relative band intensities have now been systematically compiled; completing the spectral region that lies between the more thoroughly studied terahertz and mid-IR regions. These results can be incorporated in spectral libraries and databases to enable far-IR statistical analyses to be performed on forensic samples of mixed or impure compounds.

Grid polarisers 3D-printed out of commercial acrilic resin were tested for the polariser function and showed spectral regions where the dichroic ratio and implying importance of molecular and/or stress induced anisotropy. Metal-coated 3D-printed THz optical elements can find a range of applications in intensity and polarization control of IR-THz beams. The used 3D printing method allows for fabrication of an arbitrary high aspect ratio grid polarisers. Polarization analysis of synchrotron THz radiation was carried out with a standard stretched polyethylene polariser and revealed that the linearly polarized (horizontal) component contributes up to 22% ± 5% to the circular polarized synchrotron emission extracted by a gold-coated mirror with a horizontal slit inserted near the bending magnet edge. Comparison with theoretical predictions shows a qualitative match with dominance of the edge radiation.

Domestic (Bombyx mori) and wild (Antheraea pernyi) silk fibers were characterised over a wide spectral range from THz 8 cm −1 ( λ = 1.25 mm, f = 0.24 THz) to deep-UV 50 × 10 3 cm − 1 ( λ = 200 nm, f = 1500 THz) wavelengths or over a 12.6 octave frequency range. Spectral features at β-sheet, α-coil and amorphous fibroin were analysed at different spectral ranges. Single fiber cross sections at mid-IR were used to determine spatial distribution of different silk constituents and revealed an α-coil rich core and more broadly spread β-sheets in natural silk fibers obtained from wild Antheraea pernyi moths. Low energy T-ray bands at 243 and 229 cm −1 were observed in crystalline fibers of domestic and wild silk fibers, respectively, and showed no spectral shift down to 78 K temperature. A distinct 20±4 cm−1 band was observed in the crystalline Antheraea pernyi silk fibers. Systematic analysis and assignment of the observed spectral bands is presented. Water solubility and biodegradability of silk, required for bio-medical and sensor applications, are directly inferred from specific spectral bands.

Polariscopy is demonstrated using hyperspectral imaging with a focal plane array (FPA) detector in the infrared (IR) spectral region under illumination by thermal and synchrotron light sources. FPA Fourier-transform IR (FTIR) imaging microspectroscopy is useful for monitoring real time changes at specific absorption bands when combined with a high brightness synchrotron source. In this study, several types of samples with unique structural motifs were selected and used for assessing the capability of polariscopy under this FPA-FTIR imaging technique. It was shown that the time required for polariscopy at IR wavelengths can be substantially reduced by the FPA-FTIR imaging approach. By using natural and laser fabricated polymers with sub-wavelength features, alignment of absorbing molecular dipoles and higher order patterns (laser fabricated structures) were revealed. Spectral polariscopy at the absorption peaks can reveal the orientation of sub-wavelength patterns (even when they are not spatially resolved) or the orientation of the absorbing dipoles.

A hybrid capacitor comprising mixed transition-metal sodium phosphate/activated carbon (AC) with sodium hydroxide electrolyte is reported for the first time. The sodium phosphate (maricite, NaMn1/3Ni1/3Co1/3PO4) positive material was prepared by both urea-assisted combustion and polyvinyl pyrrolidone (PVP)-assisted sol–gel syntheses. The electrochemical behavior of maricite and AC was characterized by cyclic voltammetry (CV) and charge–discharge methods. The reaction mechanism at the maricite electrode in NaOH(aq) electrolyte appears to be reversible, involving a faradaic process, while the AC shows capacitive behavior involving a non-faradaic process. The aqueous hybrid capacitor, maricite (as the cathode), and AC (as the anode) studied by galvanostatic (charge–discharge) cycling in the range of 0–1.6 V at 0.5 A g–1 exhibited a specific discharge capacitance of 45 F g–1 stable over 1000 cycles.

1-Phosphapropyne has been prepared and high-resolution (0.001 cm−1) spectra have been recorded on the far-infrared beamline at the Australian synchrotron between 1500–700 cm−1 and 400–50 cm−1. Ro-vibrational transitions of the ν8 (308 cm−1) and ν7 (1006 cm−1) fundamentals as well as the 2 ν 8 ± 2 ← v 8 ± 1 and 2 ν 8 0 ← v 8 ± 1 hot-bands have been assigned, and rotational, centrifugal distortion and Coriolis interaction parameters determined. The 2 ν 8 ± 2 ← v 8 ± 1 hot-band is an example of a particularly complex E ← E transition, for which both states are strongly Coriolis and l(2,2) coupled.

The structural characteristics of olivine-type lithium orthophosphate Li(Mg0.5Ni0.5)PO4 synthesized via solid-state reaction have been studied using X-ray diffraction, ion beam technique, scanning electron microscopy, infrared spectroscopy, transmission electron microscopy and energy dispersive X-ray analysis. The parent LiNiPO4 compound can be synthesized in olivine structure without any evidence of secondary phases as impurities. The structural quality of the parent LiNiPO4 in the absence of secondary component phases resulted in the formation of hexagonal closed packed structure. The olivine analogue compound containing mixed M (M = Mg, Ni) cations, Li(Mg0.5Ni0.5)PO4 contained Li3PO4 as a second phase upon synthesis, however a carbothermal reduction method produced a single-phase compound. The redox behaviour of carbon-coated Li(Mg0.5Ni0.5)PO4 cathode in aqueous lithium hydroxide as the electrolyte showed reversible lithium intercalation.

Experimental and theoretical investigations of the microwave and far infrared spectra of CH3COD are reported. 2883 lines were identified in the far infrared spectrum recorded using the Canadian synchrotron radiation light source. 1168 lines in v t = 0 and 700 in v t = 1 have been measured in the microwave spectrum obtained using the fast scan submillimeter spectroscopic technique. A global analysis of the new data and of already available microwave lines has been carried out and yielded values for 36 rotation–torsion parameters. The unitless weighted standard deviation of the fit is 0.9.

Fourier transform infrared emission spectra of MnH and MnD were observed in the ground X 7 Σ + electronic state. The vibration-rotation bands from v = 1 → 0 to v = 3 → 2 for MnH and from v = 1 → 0 to v = 4 → 3 for MnD were recorded at an instrumental resolution of 0.0085 cm −1 . Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant ( ω e ) for MnH was found to be 1546.84518(65) cm −1 , the equilibrium rotational constant ( B e ) is 5.6856789(103) cm −1 and the eqilibrium bond distance ( r e ) was determined to be 1.7308601(47) A.

In terahertz (THz) and far-infrared (FIR) spectroscopic measurements, weak absorption spectral features due to small quantities of test sample can be masked by undesirable etalon fringe artifacts caused by multiple reflections within a pellet or a rigid sample holder. A double-layered nitrocellulose (NC) membrane structure is proposed in this paper as an alternative holder for small quantities of either dry or wet pure (no added polyethylene powder) samples with significantly reduced etalon artifacts. Utilizing a THz time-domain spectroscopy system and a synchrotron source, we demonstrate the performance of the NC structure across the THz/FIR spectrum, benchmarking against pellets holding similarly small quantities of α-lactose powder either with or without different grades of polyethylene powder. With only pure samples to consider, scattering can be mitigated effectively in NC-derived spectra to reduce their baselines.

Olivine-type lithium orthophosphate Li(Co0.5Ni0.5)PO4 was synthesized in a solid state reaction at 800 degrees C in air. Infra-red spectroscopy, x-ray and neutron powder diffraction were used to characterize the as-prepared compound and its electro-oxidized analogue. Rietveld analysis was used to illustrate that the synthesized compound is isostructural with LiNiPO4 and LiCoPO4 with lattice parameters larger than the former and smaller than the latter. The Rietveld-refined Ni:Co ratio was found to be 0.498(4):0.502(4) and no evidence for long-range Ni: Co ordering or mixed Li/Ni/Co cation sites was found. The electro-oxidised electrode showed a mixture of two phases i.e. parent Li(Co0.5Ni0.5)PO4 and lithium extracted Li1-x(Co0.5Ni0.5)PO4 suggesting a delithiation process in aqueous electrolytes. Reversible Li transfer between a Li(Co0.5Ni0.5)PO4 electrode and an aqueous LiOH electrolyte was demonstrated.

The electrochemical performance of planar and porous zinc electrodes in an actual Zn/ MnO 2 battery using lithium hydroxide (LiOH) electrolyte has been investigated. A large discharge capacity of 220 mAh/g is delivered by porous zinc electrodes while planar electrodes only deliver 130 mAh/g. The porous anode improves the rate capability of the rechargeable alkaline battery while enhancing the utilization of the active material. Using scanning electron microscopy and IR spectroscopy, the surface morphology and composition of the Zn anodes were studied at the end of the discharge process. While zincate ions and ZnO products were found after the discharge at the surface of the planar anode, no evidence for these products was found in the porous anode. The porosity of this surface prevents the detrimental buildup of zincate ions at the anodic surface that leads to passivation.