We investigate the electronic, photocatalytic and optical properties of a fully hydrogenated indium nitride H–InN–H monolayer under biaxial strain εb and external electric field E using density functional theory. Our findings demonstrate that the H–InN–H monolayer is a semiconductor with an indirect energy gap of 2.591 eV. Under a biaxial strain or electric field, the indirect–direct band gap transition can occur and its band gap depends dramatically on the εb and E. Our analysis of band edge alignment shows that the H–InN–H monolayer can possess photocatalytic activity for water splitting when an electric field or biaxial strain is applied. The optical characteristics of the H–InN–H monolayer depends greatly on the strain. The first optical gap of the H–InN–H monolayer is at the incident energy light of 3.320 eV and the tensile strain causes the first optical gap to shift towards the visible light region.

Some twelve years ago, Nature published an article reporting an evidence for wavelike energy transfer in the Fenna-Mattews-Olson complex, a small photosynthetic antenna isolated from green bacteria [Engel et al.Nature 446 (2007) 782]. In a broader sense, this publication marks a start of a complicated series of events, which constitute a part of what could be called a quantum revolution in biology. In this paper, we revisit the past decade of development in theoretical understanding of excitation energy transfer (EET) in photosynthesis under the influence of the new quantum vision of this field. In order to set the context, we review the status of the quantum theory of EET before the field has become a part of the broader discipline of quantum biology. We rephrase some of its former concepts in terms of decoherence theory and in the language of quasi-particles, to show the place, which theoretical photosynthesis research occupied in the big picture of quantum mechanics, physical chemistry and solid state physics before the supposed quantum revolution. We examine the influence of the new quantum-biological vocabulary, established over past ten years, on the development of the field. While the field has shown steady progress, directly related to the finds of Engel et al., we demonstrate that concepts ill-defined in the context of photosynthesis research, and imported from other branches of physics, actually hinder understanding of important natural photo-physical processes. Without providing suitable equivalent or added value, they threaten to replace concepts, which tie photosynthesis research to the related disciplines of chemistry and solid state physics. We demonstrate these claims by analyzing in some detail several recent paradigmatic papers from high profile journals.

Choosing a proper representation is the first step of numerically describing wave functions or solving Schrödinger equations. One of the widely used representations is discretized coherent state representation (DCSR). However, the DCSR performs badly in computation because of its overcompleteness (non-orthogonality) and high dimension in the phase space. We present a circularly discretized coherent state representation (CDCSR) and two corresponding fast algorithms to overcome the disadvantages of the DCSR. By using the CDCSR, the function can be simply expressed as same as that in an orthogonal representation. Using two fast algorithems, we can largely simplify the computational complexity.

According to the standard theory, a spatially-extended (diffuse) double layer is assumed to occur in charged colloids (suspensions), leading to repulsive forces that might compensate, at relevant distances, the attractive molecular forces. It is shown in this paper that, in contrast with this standard double-layer theory, the electric interaction of the ions and the charged colloidal particles requires the application of the cohesion theory of electrically-interacting particles, which may lead to stabilization, or even aggregation of the colloid, independently of attractive molecular forces. The screened two-particle interaction which occurs in this case (in the dilute limit) is attractive at long distances and repulsive at short distances, with a negative minimum. Many-particle forces occur over short distances, which complicate considerably the situation. Solid and liquid phases are identified here in charged colloids (and even a non-ideal gaseous phase with attractive interaction), the equilibrium mean separation distance between the particles is estimated and the transition between various phases is discussed.

A thermal pyrolysis method, prior to a conventional rapid thermal annealing (RTA) treatment, was developed for octadecylphoshponic acid (ODPA)-modified Si samples. The thermal pyrolysis could break P−C linkage at 500 °C and release carbon impurities from silicon surfaces, because of its weak bonding energy (∼ 260 kJ/mol) in ODPA molecules. The results show that large amounts (> 60%) of C impurities are successfully eliminated. Hall effect measurements suggest that the electrical activation rate of P dopants rises up to 56.7% from 3.8%, while all C-related defects at 133 meV below the conduction band are excluded. The calculated ionization rate of P dopants is approximately 83%. The resultant ∼ 17%, assigned to Ci−Ps defects, could be further minimized by extending RTA time. Therefore, it is promising to manufacture defect-free doped Si materials by the thermal pyrolysis, together with RTA treatments.

Boron nitride (BN) has been explored these days because of its extraordinary optical, chemical and mechanical properties. BN is sensitive to its crystal structure that slight change in lattice parameters enormously change its properties. Present study deals with synthesis, characterization as well as photocatalytic applications of BN-based composite. When BN was mixed with SnO2 having tetragonal crystal structure, dissociation into smaller sheets occurred and the material oriented to (102) plane. SnO2 particles attached both sides of BN sheets provided high surface area which make the material suitable for catalytic process. Presence of large number of active sites leads to the formation of hydroxyl radicals in BN/SnO2 composite which helps during degradation of organic and colourless pollutants i.e. methyl orange dye up-to ∼92% under 7 minutes and salicylic acid in 40 minutes to ∼82%. Results suggested that BN/SnO2 composite possesses good capability for use in environmental as well as industrial applications.

We study comprehensively the uniform strain effect on the elastic, electronic and optical properties of the perovskite CsPbCl3 using theoretical calculations based on the Full-Potential Linearized Augmented Plane-Wave (FP-LAPW) method. The Generalized Gradient Approximation (GGA-PBESol) and Tran-Blaha modified Becke-Johnson exchange potential improved by Koller (KmBJ) are adopted to describe the electron exchange-correlation interactions. The compound is elastically stable and ductile. And its mechanical resistance increases with the compressive strain but decreases with the tensile stress. Based on results, CsPbCl3 is a direct semiconductor with band gap of 2.990 eV, which increases when the strain switches nature from compressive to tensile. The optical absorption of CsPbCl3 can be enhanced by applying a compressive strain, and the absorption band can be widen to 620 nm in the visible region with a compressive strain of -5%, making it suitable for photovoltaic applications. Therefore, the strain engineering on CsPbCl3 may be very useful to determine suitable parameters for applications in the optoelectronics industry.

Controlling the point defect in Li-doped ZnO is difficult. In addition, the absorption spectrum distribution in Li-doped ZnO with O vacancy (VO) has two reports of red- and blue-shift experimental predictions. The photocatalytic properties of Li doping and point defect on ZnO was studied using first-principles method based on generalized gradient approximation (GGA) plane-wave super-soft pseudopotential +U (GGA+U) to solve this problem. Compared with undoped ZnO, ZnO supercell with Li replacing Zn (LiZn) and VO, LiZn and Zn vacancy (VZn), interstitial Li (Lii) and VZn, and ZnO supercell with LiZn, Lii, and VZn have a narrower band gap and a red-shifted absorption spectrum distribution. By contrast, ZnO supercell with Lii and VZn have a wider band gap and a blue-shifted absorption spectrum distribution. The effective mass calculations show that the ZnO supercell with LiZn and VO has the smallest effective mass of carriers and can thus accelerate the separation of electron–hole pairs, thereby improving photocatalytic activity. The analysis of the electric dipole moment showed that ZnO supercell with LiZn and VO has the strongest activity of carries. This condition is advantageous for designing and preparing novel photocatalysts.

In this paper we propose a new theoretical model for describing the formation of ultracold heteronuclear RbCs molecules in excited rovibrational states of the electronic ground state X1Σ+ from combination of ultracold Rb and Cs atoms. A new scheme of association assisted by an electric field, that we call electro-association (EA), is proposed. Temperature dependent formation rates of molecules were found equal to: KEA≈10-12cm3/s at T≈0.1mK, which can be compared to other formation rates of some heteronuclear bi-alkali molecules. This model presents a different technique to create cold molecules with efficiency comparable to the photo-association (PA) technique, which requires optical pulses.

A Density Functional Theory (DFT) study of the electronic, energetic, dynamical, and mechanical properties of new glycine molecular crystals is presented here. Our search of the potential energy surface (PES) reproduces the previously reported structures for α–, β–, and γ–glycine with P21/n,P21,P31 symmetries, respectively. In addition, we report three new orthorhombic (o), tetragonal (t), and monoclinic (m) crystals with P212121,P43, and P21 symmetries. The crystals have wide band gaps, classifying them in the range of insulators. All three new phases have low mechanical hardness (< 3.2 GPa), characterizing them as soft crystals. Topological and local energetic properties of the electronic densities for the new crystalline phases of glycine have been calculated using the tools provided by the quantum theory of atoms in molecules (QTAIM) under periodic conditions. Typical NH⋯O, OH⋯O as well as secondary CH⋯O hydrogen bonds (HBs), act as the stabilizing factors resulting in large cohesive energies for the new phases of glycine crystals. Without exception, all types of HBs, for all new phases, perfectly fit the attractive region of a Lennard–Jones potential.

We present the behaviors of both dynamical and static charge susceptibilities of undoped armchair graphene nanoribbon using the Green’s function approach in the context of Holstein model Hamiltonian. Specially, the effects of magnetic field and electron-phonon coupling strength on the the plasmon modes of armchair graphene nanoribbon are investigated via calculating correlation function of charge density operators. Random phase approximation has been implemented to find the interacting dynamical charge susceptibility. The electrons in this systems interacts with each other by mediation of dispersionless Holstein phonons. Our results show the increase of electron phonon coupling strength leads to decrease intensity of charge collective mode. Also the frequency position of the collective mode tends to higher frequencies with electron phonon coupling. We also show that the frequency positions of plasmon mode of armchair nanoribbon are not affected by the increase of magnetic field. Furthermore the number of collective excitation mode increases with ribbon width in the presence of electron-phonon interaction. Finally the temperature dependence of static charge structure factor of armchair graphene nanoribbon is studied. The effects of magnetic field, ribbon width and electron-phonon interaction on the static structure factor are addressed in details.

Titanium dioxide (TiO2) anodes attract extensive attention because of their high security, good stability and low cost. But poor electronic conductivity and rate capability of TiO2 limit its practical application in Lithium ion batteries (LIBs). In this paper, we design a TiO2 based integrated electrode with binder free and electrical conductive structure through a simple and effective route.The TiO2-carbonized PAN electrode delivers a reversible capacity of 377 mAh g-1 after 100 charge-discharge cycles, which is much higher than that of commercial TiO2 electrode. The improved anodic performance can be attributed to the conductive carbonized PAN coating layer, which is beneficial to facilitate the electron transport during the lithiation and de-lithiation reactions of TiO2. Besides, the designed binderless structure effectively promotes the tight interconnection between TiO2 and current collector. This paper may provide a new perspective and approach for the modification of commercial TiO2 anodes.

The phase transitions of two nanoparticles and their corresponding bulk systems are examined by the effective-field theory with correlations. It is clarified that the transition temperatures of such small nanoparticles may become larger than those of its corresponding bulk systems, when the surface exchange interaction is selected as a large value.

The amplitude of the odd-even variation in binding energy is calculated for cationic gold clusters, Aun+,n=8-26, extracted from experimental literature data. The data are found to agree fairly well with a simple Fermi gas estimate. Motivated by this, the canonical ensemble free energies are calculated for a ladder spectrum. Experimentally observed differences in ground state dissociation free energies between species with odd and even numbers of valence electrons reaches the high temperature limit at temperatures significantly below values corresponding to the HOMO-LUMO gap. Remarkably, the asymptotic high temperature limit does not correspond to the complete disappearance of the zero temperature free energy difference. Likewise, the amount of electronically excited states are significantly higher than a simple estimate based on the Boltzmann factor of the gap energy, having implications for threshold ionization yields.

Polysulfide anions play crucial roles in the liquid phase, but they are difficult to describe in theoretical calculations. We have investigated diffuse functions dependent total energy, bond length, and molecular orbitals for disulfide dianion (S22-) in water using conventional ab initio unrestricted Hartree-Fock method (UHF/6-311G+(d)) with a polarizable continuum model (PCM, ε = 78.39) by changing ς value of diffuse functions. S22- in water turns out to be more stable than S2 and S2-, though it is too unstable to exist in vacuum so that the excess electrons will auto-detach. The optimal ς value that gives a local minimum of total energy for S22- in water is found to be 0.12. These new findings will contribute toward using more appropriate diffuse functions for other polysulfide anions as well.

The influence of a microwave radiation on the prompt fluorescence (PF) excited in molecular crystals by an ultrashort laser pulse is theoretically considered in the work. Laser pulse excites organic molecule to the lowest singlet state S1 and simultaneously produces a pair of localized triplet excitons in its singlet state. The subsequent emission from the S1 level and emission from the singlet spin component of the triplet pair combine to produce PF. Unlike the steady-state RYDMR, the pulsed method proposed in this work allows the two emission channels to be discriminated. A microwave-induced contribution to the PF-decay curve is shown to be bell-shaped and contain oscillatory component. By measuring the amplitude of these oscillations one can estimate relationship between the partial transition rates controlling the decay process.

The modified fundamental measure theory is employed to investigate the effects of wall curvature and wall-fluid interactions on the structure tangential and normal pressure of fluids confined in bispherical nanopores. Results show that the values for density and tangential pressure at the concave wall of hard bispherical pores are larger than those at the convex wall. Opposite results are obtained when a strong attraction potential is applied to the convex wall while the concave wall is a hard one. It is possible to get symmetrical profiles of density and tangential pressures with respect to two walls of a pore by varying the curvature and wall-fluid interactions. Although these two factors drastically affect the local density, pressures, and their average values, the behavior of the average values of their thermodynamic properties does not depend on them. This indicates that certain well-established bulk regularities are valid for fluids confined in bispheical pores.

This study addresses numerical investigation of dielectric properties of acetonitrile confined in Single Walled Carbon Nano Tubes (SWCNTs). Frequency dependent permittivity have been computed by assuming whether interactions among the Acetonitrile (ACN) molecules exist or not. Both axial and radial dielectric permittivity show tube diameter dependence. Static dielectric permittivity becomes larger with the diameter of the tubes but still smaller than that of the bulk state as well. Furthermore, an anomalous decrease in radial component of dielectric permittivity was observed. Bending modes and stretching modes between the Carbon atoms affect the variation of dielectric permittivities as well. Moreover, Kirkwood correlation factor, g factor, firmly influenced by the size of the tube and Knudsen region where immediate interactions of ACN molecules start to develop in the this region for narrower tubes too. Both relaxation and reorientation of Acetonitrile inside the CNTs are slower than those of the bulk state.

In this work, the rejection performance of methyl orange (MO) through molybdenum disulfide membranes in water combining electroosmosis has been studied in order to develop the 2D nanofiltration materials for waste water treatment. The laminar and homogeneous membranes could be prepared through mechanical exfoliation and vacuum filtration from MoS2 nanosheets. The results indicated that MoS2 membranes showed almost 100% retention of methyl orange within one hour, and up to 97% within four hours. Moreover, the flux showed 0.207L/m2.h for a 5.8 μm-thick membrane, which was 3-5 times higher than GO membranes. The result of XPS test and SEM-EDS have demonstrated that there is no chemisorption between MoS2 and MO, and the separation mechanism can basically owe to Donnan effect and sieve effect. This work suggests that molybdenum disulfide is an emerging filtration membrane material to increase the removal capacity of water contamination.

Room temperature ionic liquids (RTILs) have shown great potential in a wide range of applications, especially as novel electrolytes for energy generation. Understanding microscopic dynamics under variable environmental conditions provides critical knowledge of the microscopic interactions in RTILs, which are closely linked to their functionality. Here, we investigate a response of a RTIL, EmimTFSI, to application of a high pressure, up to 1.0 GPa, using quasi-elastic neutron scattering, Raman and X-ray scattering. The ionic liquid transitions from a liquid to a solid state at above ∼0.5 GPa and returns to its liquid state following full decompression. However, following such pressure application, the resulting liquid no longer possesses either cations, or anions, as individual entities, as evident from quasi-elastic scattering and Raman scattering results, respectively. We suggest that a possible cause for this behavior could be dimerization of ions, which needs to be considered when designing RTILs for moderate high-pressure applications.

Advance was made recently in identifying the nature of the Debye relaxation observed by dielectric spectroscopy in monohydroxy alcohols by other experimental techniques. Consistent with the experimental findings, the transient chain model give a good description of the origin of the Debye relaxation. Notwithstanding, a general property of the Debye relaxation remains not explained, and that is the weaker temperature and pressure dependences of its relaxation time τD(T,P) compared to τα(T,P) of the faster structural α-relaxation at temperatures approaching the glass transition temperature Tg. Based on the transient chain model for the Debye relaxation, and the Coupling Model for the α-relaxation, we have explained the difference in the temperature and pressure dependences of τD(T,P) compared to τα(T,P) quantitatively.

Novel sulfonated poly (ether-ether-ketone)/phosphonic acid-functionalized siloxane composite proton exchange membranes were prepared by sol-gel method using sulfonated poly (ether-ether-ketone) as the matrix and phosphonic acid-functionalized siloxane as the crosslinking agent. Phosphonic acid functionalized siloxane was prepared from tetra sodium of 1-hydroxyethane-1, 1-diphosphonic acid (HEDP·Na4) and 3-isocyanatopropyltriethoxysilane (IPTES). The Fourier transform infrared results suggest that HEDP·Na4 was anchored into IPTES and Si-O-Si crosslinked network was formed successfully. The prepared membranes were stable up to 220 °C without any degradation and exhibited excellent dimensional stability and mechanical performance. The proton conductivity of composite membranes increased with rising the phosphonic content, especially for AES-3 and AES-4, the proton conductivity were higher than Nafion117 at 80 °C. Besides, the proton conductivity of AES-3 was up to 0.0378 S cm-1 under 140 °C. The power density of the MEA fabricated with AES-3 could reach to 157 mW cm-2.

The monolayer self-assembled porous supramolecular networks of p-terphenyl-3,5,3′′,5′′-tetra-carboxylic acid (TPTC) that stabilized by intermolecular hydrogen bonding between four carboxyl groups at nonanoic acid/graphite interface were constructed. Scanning tunneling microscopy (STM) demonstrates that the guest molecules coronene (COR) adsorption in the pores of TPTC monolayer network. Furthermore, TPTC molecules can form the bilayer supramolecular framework and the trapping of COR guest molecules in both layers.