2-(2′-hydroxyphenyl)benzothiazole (HBT) exhibits remarkable photophysical properties, in particular intense fluorescence, both in solution and in solid state. For this reason, this compound and related ones are intensely studied for a...
Nitro-group cleavage and NO2 elimination are identified as common early-stage decomposition pathways across diverse CHNO energetic materials under shock loading. Herein, we construct a transferable deep neural network potential (NNP)...
As common defects in graphene, grain boundaries scatter phonons and carriers, leading to decreases in thermal conductivity and electrical conductivity. However, the thermoelectric transport parameters exhibit different sensitivities to grain...
Severe corrosion of mild steel constitutes a critical challenge in acidic environments, and the incorporation of corrosion inhibitors serves as a feasible strategy to alleviate this issue. Herein, electrochemical tests, surface analyses together with DFT-based first-principles calculations were adopted to assess the anticorrosion performance of Sageretia theezans extract (STE), an eco-friendly corrosion inhibitor, toward mild steel in HCl medium. Electrochemical measurements demonstrate that the inhibition efficiency of STE is concentration-dependent, with a maximum value of 99.2% at 100 mg L-1. First-principles calculations demonstrate that the main active constituents of STE, in both protonated and unprotonated states, can bind to mild steel substrates via Fe-O and Fe-C chemical bonds, verifying the occurrence of chemisorption at the molecular level.
Existing studies have not reached a consensus on the kinetics of ĊH2CHO + NO2. The available rate parameters were extrapolated from limited experiments under low temperature and low pressure conditions, and their applicability has not been validated. A systematic theoretical investigation into ĊH2CHO + NO2 kinetics is carried out at the CCSD(T)/CBS//M06-2X/aug-cc-pVDZ level. Microcanonical variational transition state theory and RRKM/master equation calculations were employed to determine rate coefficients over a range of temperatures and pressures. The major pathway proceeds via radical-radical recombination: the unpaired electron on the terminal carbon of the vinoxy radical couples with the unpaired electron of NO2 to form a closed-shell O2NCH2CHO adduct through C-N bond formation, with chemical activation leading to NO release as a competing channel. Kinetic modeling shows that incorporating these results into established reaction mechanisms for predicting major species evolution causes distinct perturbations across different models. Further refinement is recommended for the NO2 self-reaction kinetics, the reactions of CHO and CH2O with NO2 and O2, as well as the reactions of CO and CH2O with ȮH, to improve model accuracy.
Optical spectroscopy predominantly probes dipole-allowed singlet excitations, limiting access to spin-forbidden and non-dipole transitions. In polyatomic molecules, mixing between valence and Rydberg excitations further complicates spectral interpretation. Here, we combine...
ZnO is a promising wide bandgap semiconductor for photovoltaics, light emitting diodes (LEDs), and sensors. But, its intrinsic n-type conductivity limits applicability where p-type behaviour is essential. Copper (Cu) is...
Thermal transport across interfaces is a critical bottleneck in the thermal management of modern microelectronics, particularly as devices scale toward the nanoscale with increasingly high-power densities. While bulk material properties are well understood, the physics governing heat transfer at interfaces, defined by carrier transmission and scattering, remains a complex challenge. Here, we review methods and studies on interfacial thermal transport spectroscopy, bridging fundamental theory with the state-of-the-art modelling and experiments. We first examine the fundamentals of the phonon gas model and carrier coupling, followed by a detailed discussion of computational approaches ranging from atomistic Green's functions (AGF) and molecular dynamics (MD) simulations at the nanoscale to the Boltzmann transport equation (BTE) at the microscale. Then, we evaluate popular experimental techniques, such as frequency-domain thermoreflectance (FDTR), time-domain thermoreflectance (TDTR) and electron energy loss spectroscopy (EELS), emphasizing their role in resolving spectral phonon contributions. We further highlight emerging data-driven methods and machine learning approaches that accelerate physical understanding and materials discovery. Finally, we outline open challenges in characterizing spectral interfacial thermal transport within computational and experimental frameworks, as well as the persistent gaps between them. This review aims to provide a unified perspective on understanding and optimizing interfacial heat dissipation for next-generation electronic and energy devices.
We carried out first principles electron-correlated calculations using the Dunning's correlation-consistent polarized valence triple-zeta (cc-pVTZ) basis set to optimize the geometries and to compute linear optical absorption spectra of various silicon hydrides of the form Si3Hn, n = 1-4. The geometry optimization was performed using either unrestricted coupled-cluster singles-doubles (UCCSD) or coupled-cluster singles-doubles (CCSD) methodology. To corroborate the stability of the systems, we also carried out vibrational frequency analysis at the same level of theory employed for the geometry optimization. The descriptions of the excited states and the photoabsorption spectra were calculated using a time-dependent density functional theory (TDDFT) scheme. Isomers of Si3H, Si3H2, Si3H3, and Si3H4 systems were investigated, and a strong structure-property interconnection is observed - thus, spectral signatures of these conformers can be used for their optical detection and characterization. Our computed spectra are the first of their kind and hence, these could be explored in future experiments on these structures as a reference. The computed spectra are also constructive to identify hydrogenation induced defects in silicon thin films using optical experiments.
Films of linear and cyclic dipeptides as well as alanine amino acid, deposited on ZnSe windows, have been irradiated with a 12C4+ beam of 0.98 MeV u-1 at 10, 80 and 300 K. The effects of irradiation have been studied by measuring in situ the IR absorption spectrum before, during and after the irradiation. The main effect observed is film degradation due to ion-induced fragmentation and sputtering; notably the cyclic species exhibiting higher radioresistance than the linear ones. The measurements at low temperature also provide evidence of the formation of new species of lower masses. Moreover, the similarity between the IR spectra of irradiated alanine and pristine linear alanine-alanine films, suggests ion-induced peptide polymerization and supports the idea that cyclic dipeptides may have survived the harsh conditions of the early universe, contributing to possible radiation-induced pathways leading to larger organic species of potentially prebiotic significance.
Ion implantation followed by thermal annealing is a key process in semiconductor doping, where the resulting dopant distribution critically determines device performance. However, quantitatively predicting post-annealing impurity profiles remains challenging due to the complex coupling between implantation-induced defect generation and defect-mediated diffusion. Here, we develop a first-principles-based atomistic framework that combines density functional theory molecular dynamics (DFT-MD) for ion implantation with deep potential molecular dynamics (DeePMD) for large-scale annealing simulations. In this approach, all-electron DFT is used to construct accurate interatomic interactions governing implantation, while the deep potential (DP) model enables efficient and accurate simulations of defect-mediated diffusion at extended time and length scales. The DFT-MD + DP framework significantly improves the prediction of boron dopant profiles in silicon, reducing the normalized root mean square error by 50-69% compared with conventional MC/BCA + KMC methods, with excellent agreement with experimental secondary ion mass spectrometry (SIMS) measurements. The improved accuracy originates from a physically consistent description of both implantation-induced defect structures and interstitial-mediated diffusion mechanisms. In particular, the framework captures the role of excess self-interstitials and the kick-out mechanism governing boron diffusion, establishing a direct link between atomistic processes and macroscopic dopant profiles. These results demonstrate that a first-principles-based atomistic approach enables quantitatively accurate predictions of dopant transport in silicon and provides new insights into defect-mediated diffusion processes.
In this paper, a new approach is proposed to construct a two-dimensional (2D) asynchronous spectrum with a much-improved signal-to-noise level. The method produces a total number of sub-2D asynchronous spectra via a two-trace two-dimensional method (2T2D method) using n one-dimensional (1D) spectra. The final 2D asynchronous spectrum is a linear combination of this set of sub-2D asynchronous spectra with optimized combinatorial coefficients. The signs of the sub-2D asynchronous spectra are aligned to be consistent, thereby preventing undesirable cancellation of signals among different sub-2D asynchronous spectra. Suitable combinatorial coefficients derived via the Lagrange multiplier method equalize the noise variance across different sub-2D asynchronous spectra, allowing the noise to be effectively canceled out upon co-adding these sub-2D asynchronous spectra. The method is exemplified in two real-world examples. Firstly, we probed the interaction between Nd3+ and 4-tert-butylcalix[4]arene at the water/CH2Cl2 interface. The corresponding cross-peaks in the 2D asynchronous spectrum generated using the conventional method are obscured by heavy noise. However, a 2D asynchronous spectrum with well-defined cross-peak patterns is obtained using the new method from the same set of 1D spectra. The method also improved the quality of the 2D asynchronous spectrum in the benzene/I2 system. Overall, these results demonstrate that the OC-2T2D method excels at extracting highly subtle spectral variations that would otherwise be obscured by noise in conventional 2D asynchronous spectra.
Chalcogen bonding (ChB) is promising for molecular recognition and sensing of Lewis bases (LBs). Tunable optically-detected ChB-based recognition requires understanding how the nature of chalcogen influences both the ChB-forming interactions...
Determining hydrogen bonding networks and proton positions in pharmaceutical cocrystals remains challenging, particularly for microcrystalline materials and systems involving strong hydrogen bonds and partial proton transfer. Here, we demonstrate a...
The gas phase reaction of myrtenal with OH radicals has been studied experimentally and theoretically. Experiments were carried out in a flow reactor, coupled with the pulsed laser photolysis - laser induced fluorescence technique, at around 9 mbar and at temperatures ranging from 279 to 360 K. The total absolute rate constant kr was well fitted using the modified Arrhenius expression: . Electronic structure calculations were performed using density functional theory (DFT) at the M06-2X/6-311+G(d,p) level of theory. Theoretical rate constant calculations were carried out in the temperature range of 278-1000 K, using canonical variational transition state theory with small curvature tunnelling method (CVT/SCT). OH-addition to the more substituted carbon atom of the CC double bond was found to be the dominant reaction pathway, whereas OH-addition to the less substituted carbon atom of the CC double bond becomes significant only at the highest temperatures. H-abstraction from the formyl group accounts for about 25-30% within the explored temperature range. The global theoretical rate constant kCVT/SCT agrees with experimental findings within a factor of 2 to 3 and is well represented by the following expression: . The calculated global rate constant temperature dependence, however, decreases significantly for T ≥ 350 K, depicting a curvature which agrees qualitatively with the experimental results. Further investigation of the fate of OH + myrtenal products in the presence of O2, HO2, NO and NO2 leads to the final production of CO and 6,6-dimethyl-bicyclo[3.1.1]heptane-2,-3-diol. The atmospheric lifetime of myrtenal with OH radicals is estimated to range within 4-9 hours. Indoors, myrtenal could be chemically generated in poorly ventilated spaces subject to significant internal sources of terpenes like α-pinene.
Electrochemical reduction of CO2 to value-added chemicals offers a promising strategy to mitigate major greenhouse gases while enabling sustainable fuel production. Recently, two-dimensional materials have attracted significant attention as electrocatalysts...
As a probe of the initial stages of the solvation of H2O in CO2, high resolution spectra of water-(CO2)3 clusters are observed using supersonic jet expansions with a chirped-pulse Fourier transform microwave and a tunable infrared laser spectrometer. The microwave results in the 2-18 GHz range give precise descriptions of the rotational levels in the ground vibrational states of H2O-(CO2)3, D2O-(CO2)3, and two forms of HDO-(CO2)3. The infrared results in the CO2ν3 region (≈ 2350 cm-1) include two of the three possible fundamental modes for D2O-(CO2)3 as well as the stronger of these for H2O-(CO2)3 and D2O-(13CO2)3. Density functional theory structural calculations agree very well with the observed spectra. This structure has no symmetry elements and is not particularly obvious a priori.
Considerable efforts have been made to enhance the fluorescence of Carbon Nanodots (CNDs) through surface engineering or functionalization. However, these methods often alter the intrinsic properties of the CNDs. Although...
The sluggish development of Mg-ion batteries is largely attributed to the scarcity of cathode materials that concurrently offer high specific capacity, suitable intercalation voltages, and low Mg-ion migration barriers. In...
Capturing carbon dioxide (CO 2 ) directly from the atmosphere has become an essential approach in efforts to address climate change, particularly within broader carbon capture and storage frameworks. Among the materials...
