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Dynamic supersonic shock waves have a very fascinating property of inducing phase transitions in materials, as is evident from the present research work. Despite much experimental and theoretical research work that has been carried out over the past 100 years on shock waves, which has brought about significant contributions to understanding the irreversible phase transition behaviour of materials under shocked conditions, the concept of switchable phase transitions, especially from the crystalline to amorphous as a result of dynamic shock waves, is not clearly understood. In the present framework, the authors reveal and present the novel results of a switchable phase transition occurring between the crystalline (C) and amorphous (A) phases in a nickel sulfate hexahydrate single-crystal triggered by dynamic shock waves under ambient conditions, thereby following the sequence of C–C–A–C–A–C–A–C–A when the number of shock pulses is 0, 1, 2, 3, 4, 5, 6, 7, and 8, respectively. The observed results of the phase transition are convincingly reflected through diffraction, spectroscopic, and microscopic analyses. [ABSTRACT FROM AUTHOR]

Divalent ferrite nano-crystalline materials subjected to shock wave recovery analysis bringing about prolific outcomes have received widespread attention among the materials scientists due to their outstanding contribution that has fueled the enrichment of science involving high-pressure ferrites which act as the focal-point of the current research theme. On those lines, we intend to provide the Raman spectroscopic and electrochemical measurements of manganese ferrite nanoparticles (MnFe2O4 NPs) at dynamic shocked conditions. Raman spectroscopic analysis has revealed the stability of the tetrahedral (A-site) and the octahedral (B-sites) sites of Mn2+ ions as well as Fe3+ ions at shocked conditions. Cyclic-voltammetry (CV-analysis) and impedance spectroscopic measurements of the shocked samples demonstrate the electro-chemical properties of MnFe2O4 NPs whose electrical conductivity is found to have reduced while increasing the number of shock pulses. The consolidated results provide the solid evidence that the test sample's crystal structure does not undergo any crystallographic phase transitions or mixed spinel states at shocked conditions. [ABSTRACT FROM AUTHOR]

To date, according to the available sources obtained from a literature survey, shock-wave-induced switchable phase transitions are yet to be understood concretely as compared to irreversible phase transitions, which is probably due to a lack of understanding regarding the relationship existing between the crystal structure and shock pressure. In the present study, the switchable phase transition of sodium sulfate crystals has been formulated and demonstrated under shock conditions, and the observed switchable sequence of phase transitions is phase-V–V–III–V–V when the number of shock pulses is 0, 1, 2, 3, and 4, respectively. The above-mentioned switchable phase transition is categorically proven using diffraction, spectroscopic, and microscopic techniques, and the title material is suggested for use in switching molecules and sensor applications due to its higher shock sensitivity. [ABSTRACT FROM AUTHOR]

In this context, we report the acoustic shock wave processing on amorphous Carbon quantum dots (a-CQD) such that its degree of graphitization and magnetic properties are analyzed. Analytical techniques such as the Raman spectrometer, high resonation–transmission electron microscopy (HR-TEM) and vibrating sample magnetometer (VSM) are utilized to understand the structural, morphological and magnetic properties changes under shocked conditions. The Raman spectroscopic data reveal that the I D /I G ratio is slightly reduced under shocked conditions and the observed values are 0.78, 0.77 and 0.75 for the respective 0, 150 and 300 shocked conditions. The formation of ultra-short-range graphitic nanostructures is confirmed by HR-TEM results at the 300-shocked condition. The most convincing and supporting results for the enhancement of the degree of graphitization are found by the outcome of the magnetic properties such that the saturation magnetization (Ms) is found to be linearly reduced with respect to the number of shock pulses and the observed values are 0.869, 0.757 and 0.710 emu/g for the 0, 150 and 300 shocked conditions, respectively. The electrical resistance of the a-CQD is found to be linearly reduced with respect to the number of shock pulses due to the reduction of sp3 carbon networks. The formation of crystalline graphitic nanostructures in amorphous CQD is explained on the basis of the hot-spot nucleation mechanism. Based on the obtained Raman, HR-TEM and VSM results, during the shocked conditions, slight enhancement of the graphitization is observed; however, from the structural stability point of view, the Carbon dots have high shock resistance than that of the amorphous carbon nanoparticles, multi-wall carbon nanotubes, and reduced graphene oxide nanoparticles. Hence, the title quantum dots can be strongly considered for the applications of device fabrication. [ABSTRACT FROM AUTHOR]

Over the years, metal oxides have been leveraged to create several intriguing novel antibacterial active materials such that while finding the ways and means to increase efficiency, rare earth elements are found to have often served as potential optical dopants such that an optimistic en route to achieve the same, branched Sm‐doped CuO nano‐lanceolates were synthesized employing a wet chemical approach. The samples were then annealed at three distinct temperatures, which were fixed to 300 °C, 400 °C, and 500 °C. The nano‐lanceolates have crystallized in the monoclinic phase, according to the XRD analysis. The SEM image of Sm‐doped CuO captured at a magnification of 2 μm reveals a branched morphology, with multiple nano‐lanceolates stacked in a stem. TEM image reveals that the width of a typical nano‐lanceolate attached to a stem and its tip are found to be 87 nm and 212 nm, respectively and the obtained EDS data validate that elements including Cu, Sm, and O are present in the doped sample. The UV‐visible spectra of the annealed samples indicate that the sample annealed at 300 °C (1.43 eV) has a larger band gap than the other samples. The sample that was annealed at 400 °C has endured defect emissions that are more intense than those of other samples, according to the obtained PL spectra. In addition to these fascinating findings, the samples annealed at 300 °C, 400 °C and 500 °C exhibit a zone of inhibition of 23 mm & 24 mm, 11 mm & 12 mm and 12 mm & 11 mm, respectively for the two tested bacterial strains which authenticate that the 300 °C annealed Sm‐doped CuO nano‐lanceolate deactivates the two pathogenic bacteria more effectively compared to the other samples. As a consequence, the Sm‐doped CuO nano‐lanceolates at 300 °C could potentially be an effective alternative for antibacterial materials, particularly in biomedical applications [ABSTRACT FROM AUTHOR]

• Crystallographic phase stability of the poly-crystalline α-Glycine is reported at shocked conditions. • The results found that the α-Glycine is highly stable phase at shocked conditions. • It can be suitable for high temperature and high pressure device applications. High pressure experimental studies on amino acids have gained incredible attention over the past few years in variety of research areas such as materials science, geophysics, pharmaceutical sciences, and cosmo-chemistry. On en-route to the current experimental work, one of the elegant amino acid samples of α-Glycine is preferred in order to reveal its nature of crystallographic phase stability as and when exposed to dynamic shock waves thereby subjecting it to diffraction and microscopic analyses. Considering the observed results from the various analytical techniques, it is authenticated that the title sample does not undergo any kind of structural transition under shock wave exposed situations. On the other hand, the test sample has generated a few new shoulder peaks and diffraction peaks under shocked conditions. The outcome of the attained phase stability is well substantiated by the previous static high-pressure reports. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of Cd-doped BaTiO 3 nanoparticles of the series Ba 1-x Cd x TiO 3 (x = 0.1 %, 0.3 % and 0.5 %) via facile sol-gel route. • Increase in doping content of Cd leads to a change in the phase composition of the tetragonal BaTiO 3 with the dominance of the BaTi 2 O 5 phase. • The core-level XPS study carried out gives direct evidence of cation vacancies. • Cd2+ substitution significantly reduces the optical bandgap of the BaTiO 3 nanoparticles from 3.14 to 2.78 eV. • 0.3 % Cd doped BaTiO 3 leads to the gaining of small saturation magnetization (M s = 5.40 ± 0.02 × 10-3 emu/g). In order to explore the potential role of non-magnetic cadmium (Cd) in establishing room temperature ferromagnetism (RTFM) in diamagnetic BaTiO 3 , the analyses of the structural, optical and magnetic properties of non-magnetic ions Cd-doped BaTiO 3 nanoparticles of the series Ba 1-x Cd x TiO 3 (x = 0.1 %, 0.3 % and 0.5 %) are successfully accomplished making use of the samples synthesized via facile sol–gel route. The X-ray diffraction and Raman scattering analyses demonstrate that doping with Cd leads to a change in the phase composition of the tetragonal BaTiO 3 with the dominance of the BaTi 2 O 5 phase. The core-level XPS study carried out gives direct evidence of cation vacancies due to the richness of lattice oxygen content in the investigated sample at x > 0.1 %. The Cd2+ substitution significantly reduces the optical bandgap of the BaTiO 3 nanoparticles from 3.14 to 2.78 eV such that it enhances the PL visible emission. Ferromagnetism originates from the contributions of lattice contractions due to the structural deformation, defect formation and cation vacancies. Among all these samples, 0.3 % Cd doped BaTiO 3 leads to the gaining of small saturation magnetization (M s = 5.40 ± 0.02 × 10-3 emu/g). [ABSTRACT FROM AUTHOR]

A vibrant non-linear optical single crystal of cadmium chloride doped L-alanine p-toluene sulfonic acid (LAPTCd) was grown by slow evaporation. XRD analysis was carried out and obtained the cell parameter for the grown crystal. The grown LAPTCd crystal belongs to the orthorhombic crystal system with non-centro symmetric space group P212121. The presence of the dopant was confirmed from an energy dispersive X-ray analysis. FT-IR and FT-Raman spectra were recorded and the presence of different functional groups and vibrations confirmed in the grown crystal. The UV–Vis–NIR absorption and transmittance spectrum shows that the crystal has a good optical transparency within the range 200–800 nm. The optical parameters have also been calculated, and it has a lower wavelength cutoff at around 235 nm. The optical energy band gap of the crystal was calculated from Tauc's Plot and it is 5.24 eV. The fluorescence spectrum of the crystal reveals that the excitation wavelength is 489.97 nm. The thermal stability and the melting point of the crystal were analyzed by TG/DTA. The efficiency of second harmonic generation of the LAPTCd crystal is found to be 0.7 times more that of KDP crystal. [ABSTRACT FROM AUTHOR]

Abstract: 3,6-Bis (2 pyridyl) pyridazine has been synthesized and characterized by NMR, XRD and elemental analyses. The vibrational studies were carried out by using FTIR and Raman spectroscopy and the modes of vibrations were analysed and compared with the theoretically calculated values. The nonlinear optical property of the title compound was examined by Kurtz–Perry method and Hyper Raleigh scattering with the fundamental wavelength of 1064nm. This compound possesses less SHG efficiency but large first hyperpolarizability. [Copyright &y& Elsevier]

In recent years, the investigation of the effect of shock waves on crystalline materials has emerged as a prolific research area in materials science branch. The impact of shock waves on K 2 SO 4 was investigated such that the molecular and structural stabilities under pre and post-shock wave loaded conditions at Mach number 2.2 with 50 and 100 shocks were established. Molecular stability of the test samples has been identified making use of FTIR spectrometer and the structural stability of the samples has been investigated by a Powder X-ray diffractometer (PXRD) which reveals that shock waves induce lattice orientational changes and micro distortions but, the original crystal system is not affected. The above-mentioned crystallographic studies show the impressive physical properties of K 2 SO 4 which also has a stable crystal structure under shock wave loaded conditions. A comparison of single and poly-crystalline structural responses has been made with respect to the number of shock pulses. The fascinating findings of the shock wave impacts on K 2 SO 4 samples are clearly discussed in this article. • Crystallographic phase stability of the poly-crystalline and single crystalline K 2 SO 4 at shocked conditions is reported. • FT-IR and XRD results show the stable crystal structure of poly-crystalline samples at shocked conditions. • Poly-crystalline K 2 SO 4 sample has relatively high structural stability and shock resistance compared to the single crystal. [ABSTRACT FROM AUTHOR]

As per the literature reports available so far, there are numerous experiments that have been conducted and demonstrated on the crystallographic phase stability of a variety of materials such as metals, inorganic and organic materials by the impact of the shock waves. In the present course of work, we have selected one of the simple metal complex hydrate materials of copper sulfate pentahydrate (CuSO 4 ·5H 2 O) for shock wave recovery experiment so as to examine the phase stability and shock wave induced dehydration process since it has a high possibility of undergoing phase transition with the sequence of 5H 2 O/3H 2 O/H 2 O. The molecular and crystallographic phase details have been examined by Raman spectroscopy and powder X-ray diffractometry (PXRD). Surprisingly, as per the observed spectroscopic and diffraction studies, the title material has not undergone any phase transition. [Display omitted] • Crystallographic phase stability of the poly-crystalline CuSO 4 ·5H 2 O at shocked conditions is reported. • Raman and XRD results show the stable crystal structure of poly-crystalline samples at shocked conditions. • Poly-crystalline CuSO 4 ·5H 2 O sample has high structural stability and shock resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Shock wave induced disorder into order graphite structure is reported. • The control and 750 shocked I D /I G ratio values are 0.709 and 0.251. • The correlation of the magnetic properties and degree of crystalline nature is discussed. • The proposed technique is highly suitable for the synthesis of large-scale crystalline graphite. The existence of the long-range order under extreme conditions is a highly unusual structural concept that remains one of the top-class fundamental questions for every high-pressure researcher to resolve. In the present study, it is probably the first time that we report the acoustical shock wave-induced conversion from disordered graphite (I D /I G - 0.709) to highly-ordered graphite (I D /I G - 0.251) at the 750-shocked condition and the obtained long-range ordering is comprehensively examined by a few representative microscopic observations which include the Raman spectroscopy, photoelectric X-ray spectrometry and transmission electronic microscopy. Furthermore, the shock wave-induced hot-spot nucleation mechanism for the graphitization is put forward in combination with the outcome of the obtained magnetic, electrical and thermal experimental data. All of these acquired results clearly demonstrate that by using the acoustical shock waves, it is possible to provide one distinctive insight into deeply disclosing the large-scale synthesis of crystalline graphite, which has the potential to be utilized extensively in future commercial applications. [ABSTRACT FROM AUTHOR]

Switchable nanostructured materials with a low-cost and fast processing have diverse practical applications in the modern electronic industries, but such materials are highly scarce. Hence, there is a great demand for identifying the externally stimulated solid-state switchable phase transition materials for several industrial applications. In this paper, we present the experimentally observed solid-state molecular level switchable phase transitions of nanocrystalline iron oxide materials: {α-Fe2O3 (R-3c) to Fe3O4 (Fd-3m) and Fe3O4 (Fd-3m) to α-Fe2O3 (R-3c)} under dynamic shock wave loaded conditions, and the results were evaluated by diffraction, and vibrational and optical spectroscopic techniques. To date, this is most probably the first report which demonstrates the simultaneous molecular and crystallographic switchable-phase-transitions enforced by dynamic shock waves such that the title material is proposed for sensors and molecular switching applications. [ABSTRACT FROM AUTHOR]

This article carries the findings of the effect of shock waves on glycine phosphite (GPI) powder samples which have been investigated under pre and post shock loaded conditions with the shock pulses of 50 and 100 at the Mach number of 2.2. Molecular structural stability and crystal structural stabilities have been established by Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffractometry (XRD). From XRD studies, it has been observed that there is change in crystalline peak intensity, peak distortion and formation of new peaks in shock wave loaded samples whereas no alteration in the original crystal system. There is no change observed in FTIR profiles at shock loaded conditions. The obtained crystallographic studies prove with substantial evidence that the crystal has molecular stability and stable crystallographic structure against the impact of applied shock waves. On the other hand, many of the crystalline planes have disappeared and re-appeared with respect to number of shock waves but maintaining the same crystallographic phase. From the shock wave impact study; the authors suggest that GPI crystal, particularly (21-1) orientation, is suitable for devices used in harsh environment and high power laser application due to the relative stability of the crystalline properties. Image 1 • Molecular and crystallographic phase stabilities on GPI powder samples at shocked conditions are reported. • FTIR results reveal that, GPI sample has spectacular molecular stability at shocked conditions. • XRD results show that stable crystal structure stability at shocked conditions. • Particularly (21-1) orientation is highly suitable for device applications due to high shock resistance. [ABSTRACT FROM AUTHOR]

Today's advanced science and technology has witnessed extensive efforts put forth by researchers whose persistent work has been continuing quite consistently to find high shock resistant and technologically important device materials. Ferrites are right at the top in terms of contribution for the making of modern electronic and spintronics devices which are predominantly used in magnetic sensors as well as data storage applications. On the other hand, several ferrite materials do not fulfill the real practical requirements of the device engineers even though they have the required functional properties for device fabrications. Hence, the journey of finding ideal materials for device fabrication is still an ongoing arduous process. On this context, we have made systematic investigation of unearthing and understanding the properties and especially the stability of MnFe 2 O 4 NPs at shock wave loaded conditions. Powder X-ray diffractometer (PXRD), Ultra-Violet diffuse reflectance spectroscopy (UV-DRS) and vibrating sample magnetometer (VSM) techniques have been undertaken so as to find out the crystallographic, electronic and magnetic phase stabilities at shocked conditions. The observed XRD, UV-DRS and VSM studies reveal that the title ferrite NPs has high shock resistant behavior so that it is suggested for the application of device fabrication. Image 1 [ABSTRACT FROM AUTHOR]

In the present research article, authors have experimentally evaluated the shock wave resistant properties of technologically potential materials of the anatase and the rutile phase TiO2 nanoparticles at the dynamic shock wave loaded conditions. The shock wave resistant behavior has been quantitatively drawn utilizing the crystallographic phase stability of the test samples for which the required crystallographic information has been extracted from the powder XRD patterns. Based on our observed experimental results as well as the respective interpretations, it is strongly authenticated that Rutile TiO2 NPs are suitable candidates for aerospace and defense industrial applications of materials fabrications because of the outstanding shock resistant properties than that of Anatase TiO2 NPs which undergo the crystallographic phase transition of rutile-TiO2 at shocked conditions. [ABSTRACT FROM AUTHOR]

Rapid progress has been documented during the last couple of years in understanding the crystallographic structural features of a few functional materials that have been achieved under dynamic shock wave loaded conditions. In this context, we report the crystallographic and electronic phase stability of shock wave loaded Cerium oxide nano-crystalline (CeO 2 NPs) material and the results have been evaluated by X-ray diffraction (XRD), Raman spectroscopy and ultra-violet diffuse reflectance spectroscopy (UV-DRS). XRD and Raman spectroscopic results show that the title material doesn't undergo any crystallographic phase transitions. UV-DRS spectral results demonstrate that the Ce4+ ionic state is not affected by the impact of shock waves. The obtained FE-SEM micrographs provide the substantiation for the stability of the sample. Based on the observed results, the title material can be suggested for the making of medical glassware, spaceship windows and technological applications of coating. [ABSTRACT FROM AUTHOR]

The present work deals with the understanding of the integrated experimental and theoretical study of the molecular structure and vibrational spectra of N-allyl-N-ethylformamide (NAEF). Density functional theory (DFT) calculations were used to study the subject molecule, N-allyl-N-ethylformamide (NAEF), utilising the B3LYP method and the basis set 6-311++G (d,p). Geometrical parameters and the structure of NAEF were computed such that global descriptors and reactive sites were obtained. Frontier's analysis of molecular orbital energy demonstrates that the molecule's charge exchange is considerably high. Non-linear optical properties of N-allyl-N-ethylformamide (NAEF) were computed and compared with the standard material of urea. The vibrational assignments were analysed for the existence of the probable functional groups and tabulated. The thermodynamic functions were computed at different temperatures and listed accordingly. NMR spectroscopy and quantum computational chemistry methods have been employed for the understanding of the structures of NAEF. Moreover, different techniques such as topological analysis and drug-likeness were utilised to determine the structure and other properties of NAEF. The molecular docking study could determine the residue with the highest docking score (lowest binding energy) and the most non-covalent interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Crystallographic phase stability of the poly and single crystalline lead nitrate at shocked conditions is reported. • XRD and Raman results show the stable crystal structure of poly-crystalline samples at shocked conditions. • Poly-crystalline lead nitrate sample has relatively high structural stability and shock resistance compared to the single crystal. In the present work, we report the crystallographic structural stability of the poly-crystalline lead nitrate samples at shocked conditions with which a systematic comparison is made for the previously reported single-crystalline lead nitrate crystal at shocked conditions. X-ray diffractometry (XRD) and Raman spectroscopic measurements have been performed to assess the crystallographic structural stability of poly-crystalline Pb(NO 3) 2 samples at shocked conditions and the observed XRD and Raman results disclose that the title poly-crystalline samples retain the original crystallographic structure even at 100 shocked conditions interacting with the shock waves of 2.2 Mach number. But the single crystals of Pb(NO 3) 2 undergo crystalline to amorphous phase transition at shocked conditions. Based on the observed results, poly-crystalline samples have higher-structural stability than that of single crystals. The outcome of this work provides glimpses of possible further contributions to crystal engineering for the design of new materials with specific physical and chemical properties. [ABSTRACT FROM AUTHOR]

In this work, we report that flower shaped architecture of ZnO assembled by individual nanopetals of an average thickness ∼93 nm has been achieved by selective self – etching method. The presence of oxygen deficiency is confirmed by EDX and ATR measurements. ZnO nanopetals prepared at 80 °C exhibit enhanced polychromatic defect emissions of blue, green and red (BGR) as compared to samples annealed at higher temperatures. The improved luminescence emission of BGR is attributed to the higher lattice strain and dislocation density induced in ZnO due to native defects. As the annealing temperature is reduced, the dislocation density increases from 7.60 × 10 13 to 3.99 × 10 15 lines/m 2 , whilst, lattice strain increases from 0.0079 × 10 −3 to 1.81 × 10 −3 . The observed high luminescence emission is due to flower shaped architecture making it suitable for the fabrication of solid-state white light emitting diodes. [ABSTRACT FROM AUTHOR]

An organic nonlinear optical crystal of L-histidinium-4-nitrophenolate 4-nitrophenol (LHPNP), was grown by employing the conventional growth process of slow evaporation method. The grown LHPNP crystal was characterized by the spectral measurement (FTIR, UV-Visible, and PL) and Vicker's hardness test. The grown crystal was found to be in the system of monoclinic with non-centrosymmetric space group P21 with dimension 12 × 9 × 6 mm3. The optical band gap value of the LHPNP crystal is Eg = 2.71 eV. The dielectric studies (dielectric constant, dielectric loss and ac conductivity) of the grown crystal were measured for the frequency ranging between 100 Hz and 1200 Hz. The thermal stability of the grown crystal has been put forth by the standard thermal method of TG-DTA. The LDT analysis was carried out making use of Q-switched Nd: YAG laser and the value of LDT is estimated to be greater as compared to KDP. The SHG efficiency of the grown crystal of LHPNP is 3.5 times greater than that of a standard KDP crystal. The Hirshfeld Analysis has been carried out to understand the crystal surface properties, stability and intermolecular interaction of the LHPNP crystal. [ABSTRACT FROM AUTHOR]

In this letter, we demonstrate the dynamic shock wave induced order-disorder type phase transition exhibited by sodium nitrate single crystal and the results have been evaluated by diffraction, spectroscopic and microscopic techniques. The changeover of order into the disordered phase of NaNO 3 crystal at shocked conditions is due to the occurrence of rotational disorder of planer anions (NO 3). [ABSTRACT FROM AUTHOR]

• Tuning of SPR of silver nano particles by shock waves is demonstrated. • SPR peak gets blue shift while numbers of shock waves increased. • Alternative method is proposed for tuning the SPR peak of silver NPs. • Tri-angle correlation between structure-optical –morphological studies is explored. The present research article demonstrates the findings of the fine tuning of surface plasmon resonance (SPR) and the relationship between structural, optical and morphological properties of shock wave loaded silver nanoparticles (Ag NPs). The characteristics of structural, optical and morphological properties of Ag NPs are evaluated by powder XRD (X-ray powder diffraction), UV–Vis (ultra violet- visible) spectroscopy and SEM (scanning electron microscopy) technique, respectively. The test material of Ag NPs is subjected to the shock wave loading with 50,100 and 150 shock pulses, respectively. The PXRD results reveal that the degree of crystalline nature and grain size of the crystal is significantly reduced by the impact of shock waves. The UV–Visible spectrum reveals that the control Ag NPs absorption band at 514 nm has given rise to blue shift (514–403 nm) at 150 shock wave loaded samples. The SEM images reveal that the particle size is considerably reduced by the impact of shock waves with respect to number of shock waves. The tri-angle correlation of structural, optical and morphological properties of shock wave loaded Ag NPs is explored. [ABSTRACT FROM AUTHOR]