The magnetic properties of mixed spin-1/2 and spin-S (S>1/2) Ising ferrimagnets on a simple cubic lattice with single-ion anisotropy acting on spins S atoms, was investigated using Monte Carlo ...calculations. We determined as a function of the crystal field (d), the ground state phase diagrams for different values of S and shown that those phases are separated from each other by second-order phase transitions. We also investigated the effects of crystal field on the critical temperature by calculating the finite-temperature phase diagrams for different values of S. In addition, we found that systems with integer spins S exhibit compensation points for 2.75<d<3.
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•MMA is an insulator due to its wide band gap of 6.20 eV.•trans-MMA has a dielectric constant close to that of good insulators; while cis-MMA exhibits a dielectric behaviour close to ...that of polymeric substances.•MMA isomers exhibit weak optical properties such as second- and third-order optical susceptibility and cannot suitable for second and third harmonic generation.•Both forms of MMA absorb and emit mainly in the UV and that the Stokes shift of MMA is low, reducing its potential use in devices such as solar cells.•The conformation enhances second-order NLO response by at least 2 times when moving from cis- to trans-MMA, whereas the third-order response is almost unaffected.
Using Density Functional Theory (DFT) and time-dependent DFT (TD-DFT), we studied a compound widely used in daily life, namely: Methyl Methacrylate (MMA) monomer in its two stable isomers, cis-MMA and trans-MMA. The impact of conformation on the optical and electronic properties of MMA was highlighted. Structural parameters and thermodynamic properties were also assessed, and allowed to discuss the stability and reactivity of this compound. In addition, analysis of optoelectronic and electronic properties, global reactivity descriptors, natural bond orbital (NBO), and hole and electron reorganization energies was performed. The absorption and fluorescence properties, as well as the linear and nonlinear optical (NLO) properties of MMA were also investigated. The findings show that MMA is an insulator due to its wide band gap of 6.20 eV. It also exhibits good optoelectronic properties with high average electric field values of about 5.90 × 109 Vm−1 for cis-MMA and 5.42 × 109 Vm−1 for trans-MMA and high electric displacement values of at least 14.65 × 10-2 cm−2 for cis-MMA and 14.33 × 10-2 cm−2 for trans-MMA, suggesting a potential use for the design of piezoelectric and pyroelectric materials. In addition, trans-MMA has a dielectric constant close to that of good insulators; while cis-MMA exhibits a dielectric behaviour close to that of polymeric substances. Further, these materials are thermodynamically stable in its two conformations, with a good reactivity which can lead to good ability of polymerization. The analysis of the UV–vis spectra revealed that both forms of MMA absorb and emit mainly in the UV and that the Stokes shift of MMA is low, reducing its potential use in devices such as solar cells. At NLO level, MMA isomers exhibit weak optical properties such as second- and third-order optical susceptibility and cannot suitable for second and third harmonic generation; however, the conformation enhances second-order NLO response by at least 2 times when moving from cis- to trans-MMA, whereas the third-order response is almost unaffected. In addition, the conformation also affects the electronic and optoelectronic properties of MMA.
Hartree-Fock (HF) and Density Functional Theory (DFT) were used to investigate the structural, optoelectronic, thermodynamic and nonlinear optical properties of two styrylquinoline monomers; the ...virgin styrylquinoline monomer (M1) and the derivative monomer (M2) with the NO2 group. The results show that these two materials have good optoelectronic properties with respect to very high electric fields in particular from 3.50 × 109 Vm-1 up to 5.52 × 109Vm−1. In addition, the substitution of the H atom by the nitro group induces an increase in both ionization potential and electronic affinity, as well as a reduction in the fundamental electronic gap. The energy gap value of 3.82 eV for M1 and of 3.43 eV of M2, allows us to conclude that our molecules are semiconductors and find applications in the design of solar cells. The determination of thermodynamic properties has revealed thermodynamically stable materials with significant reactivity that are suitable for reactions with other compounds. Further, the high values of linear and nonlinear optical properties led us to conclude that these materials have very good linear and nonlinear optical properties and therefore can be used in telecommunication and signal processing.
•The structural parameters and thermodynamic analysis have revealed thermodynamically stable materials.•The energy gap values of 3.82 eV for M1 and of 3.43 eV of M2, show that they are the semiconductor materials.•The two molecular systems exhibit good linear and nonlinear properties.•The reactivity of monomers containing styrylquinoline is improved by the substitution of the H atom by the nitro group.•Higher refractive index than glass can be used under strong electric fields of the order of 3.50 × 109 Vm-1 up to 5.52 × 109Vm−1.
Hartree-Fock (HF) and Density Functional Theory (DFT) studies were conducted to assess the impact of potassium doping on the thermodynamic, optoelectronic, electronic and nonlinear optical properties ...and on the reactivity of photochromic polymers containing styrylquinoline fragments. Doping was carried out on the virgin monomer (M1) and on the derivative monomer (M2) with the nitro group NO2. Three doped monomers were investigated including, the monomer M3 obtained from M1 by substituting the H atom with a potassium, the monomer M4 by substituting two H atoms and the monomer M5 obtained from M2 by substituting the H atom. Findings proved that the use of potassium and the nitro group is an excellent process to improve the electronics properties of styrylquinoline virgin monomers. In fact, the energy gap decreases from 3.82 eV for M1 to 3.02 eV and to 2.92 eV for M3 and M4, respectively; while the decrease from 3.43 eV for M2 to 2.52 eV for M5 was observed, thus demonstrating the good semiconductor character of the obtained compounds with relevant applications in the manufacture of solar cells. Likewise, the fundamental gap decreases from 6.50 eV for M1 to 5.34 eV and to 4.62 eV for M3 and M4, respectively; while the decrease from 6.11 eV for M2 to 5.21 eV for M5 was observed; thus demonstrating an improvement in the reactivity of our doped monomers. In addition, potassium doping is an appropriate method to enhance optoelectronic properties of styrylquinoline virgin monomers. Thus, the refractive index of our doped monomers is greater than that of glass, which is a reference in optic and can be used under high electric fields of the order of 1.90×109 Vm−1 for monomer M4 up to 7.01×109 Vm−1 for M3 and to 10.89×109 Vm−1 for M5. Finally, the strong enhancement of the linear and nonlinear optical (NLO) properties that we observed leads us to conclude that these doped monomers can be appropriate candidates in devices requiring good NLO properties.
Styrylquinoline; Doping; HF/DFT; Nonlinear optical properties; Electronic properties; Energy gap
Computational studies based on Density Functional Theory (DFT) and time-dependent DFT (TD-DFT) were used to determine molecular and thermodynamic parameters, optoelectronic and electronic properties, ...as well as chemical descriptors, UV–vis spectra and nonlinear optical response of the chromophores of 2-Styrylquinoline (M01) and 2-(3-nitrostyryl)quinoline (M02). We evaluated the impact of the substitution of the hydrogen atom in M01 by the nitro group (NO
2
) to obtain the molecule M02. The results show very good optoelectronic properties with respect to very high electric fields of the order of 1.43 × 10
9
Vm
−1
for M01 up to 5.26 × 10
9
Vm
−1
for M02. The energy gap decreases from 3.94 eV for M01 to 3.56 eV for M02; which suggest that they are semiconductors. In addition, these two molecules exhibit ionization potential (IP) and electron affinity (EA) quite close to those of Alq
3
and could therefore be good candidates for the manufacture of Organic Light-Emitting Diodes (OLED). The chemical descriptors were assessed and allowed us to discuss the stability and reactivity of our molecules. Thus, the addition of the nitro group to the virgin 2-Styrylquinoline decreases the reactivity and stability of the 2-Styrylquinoline. The analysis of the IR and Raman vibrational spectra shows several peaks between 100 cm
−1
and 3200 cm
−1
of which the most intense for the molecule M01 are attributed to the stretching mode of the C–H bond in the phenyl ring and the C=C double bond in the quinoline ring. For the M02 molecule, stronger peaks were assigned to the stretching mode of the O–N and N–C bonds. The analysis of the UV–vis spectra showed that the maximum absorption wavelength of M01 is 334.80 nm and that of M02 is 375.37 nm; both located in the ultraviolet. The high values of first (
β
T
) and second (
γ
¯
) hyperpolarizability showed that both molecules have very good nonlinear optical properties and thus can be used for second and third harmonic generation.
Using density functional theory, we have studied the intrinsic properties of styrene. First, we determine the optimized structures, structural parameters and thermodynamic properties to make our ...simulations more realistic to experimental results and check the stability. Second, we investigate optoelectronic, electronic and global descriptors, transport properties of holes and electrons, natural bond orbital analysis, absorption and fluorescence properties. Finally, we study nonlinear optical (NLO) properties: first- and second-order hyperpolarizability, second and third-order optical susceptibilities, hyper-Rayleigh scattering hyperpolarizability, electro-optical Pockel effect, direct current Kerr effects and quadratic refractive index. The bandgap energy E g = 5.146 eV and dielectric constant ε r = 3.062 show that styrene is a good insulator with an average electric field value of 4.43 × 10 8 Vm −1 . Thermodynamic findings show that our molecule is thermodynamically and chemically stable. Electron and hole reorganization energies of 0.393 and 0.295 eV, respectively, show that styrene is more favourable to hole transport than electron transport. Styrene is transparent with linear refractive index n = 1.750 and quadratic n 2 = 1.748 × 10 −20 m 2 W −1 . At the NLO, styrene has a non-zero value of β H R S , which confirms the existence of first-order NLO activity. Globally the study shows that the styrene monomer is suitable for the architecture design of new polymer materials for NLO applications and optoelectronic by functionalization.
Density functional theory (DFT) calculations of the antimalarial drug dihydroartemisinin (DHA) functionalized on the carbon nanotube (CNT) were carried out in gas phase and in solution to investigate ...the role of fCNTs as a nanovector for the targeted delivery of the DHA drug and to predict their chemical descriptors and electronic and nonlinear optical (NLO) properties. The results of the geometric optimization indicate that the functionalization does not change the molecular structure of DHA. Based on our findings of binding and solvation energies, two energetically stable configurations were identified in 1st (fCNT1-2) and 2nd (2fCNT1-2) functionalization. For these stable configurations, the energy gap value goes from 1.52 eV for the (5,5) single wall pristine CNT to 1.27 eV for the 1st functionalization and to 1.06 eV for the 2nd functionalization regardless of the considered media; which gives these nanostructures excellent semiconductor properties. Findings from global reactivity descriptors show that the reactivity of the functionalized CNT is strongly improved in solvent media and that the stability of DHA decreases while its reactivity increases during the functionalization. Thus, the fundamental gap (Ef) in gas phase decreases from 3.65 eV for the virgin CNT to 3.30 eV for fCNT2 and to 3.02 eV for 2fCNT2. On the contrary, in water Ef goes from 1.20 eV for the virgin CNT to 0.95 eV for fCNT2 and to 0.74 eV for 2fCNT2; demonstrating an improvement in the reactivity of our fCNTs as nanovectors for targeted delivery of DHA drug. Finally, our findings show that these nanostructures may also have good NLO properties and can be promising materials for NLO applications.
Cordierite (2MgO·2Al2O3·5SiO2) is a thermal resistant ceramic presenting both low thermal expansion and electrical conductivity along with good chemical and mechanical properties. Thereby, it is ...suitable as material for manufacturing electric insulators, catalysis, refractory and porous ceramics. Solid-state reaction is the most common method for cordierite preparation. For this purpose, different mixtures including clay, alumina, talc, sand, diatomite and gibbsite are used. The present study is devoted to the preparation of cordierite-based materials using two mixtures of kaolin, talc and bauxite. Hence, prismatic specimens were shaped and tested to uniaxial compressive strength and heated in the range of 1200–1400°C. The fired specimens were investigated via X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Also, physical (firing shrinkage, water absorption, bulk density) and mechanical (bending strength) and dielectric properties of the fired bodies were measured as a function of temperature. The results showed that the fired bodies of the mixture composed of 50% by mass of kaolin, 20% by mass of talc and 30% by of mass of bauxite together with high sintering temperature (1400°C) resulted in the formation of abundant amount of cordierite in conjunction with mullite, cristobalite and pseudorutile. Also, there was increase of firing shrinkage, bulk density and bending strength. These changes were essentially linked to amount of new phases that were formed. Water absorption declined with increase of sintering temperature which was related to the reduction of porosity due to the formation of vitreous phase. The mixtures of kaolin-talc-bauxite which were fired at the range of 1300–1400°C exhibited dielectric constant values varying between 20.3 and 2.8 along with dielectric loss tangent which varied between 0.1316 and 0.0002 at room temperature of the laboratory. The two mixtures can be considered as promising materials for both ceramic and electronic applications.
•Ceramic bodies were produced from two mixtures of kaolin-bauxite -talc.•The mixture with great quantity of talc led to ceramic bodies that were made up of cordierite as major new mineral.•The mixture with great quantity of kaolin and low amount of talc led to cordierite and mullite as major new minerals.•The fired bodies exhibited both good ceramic and dielectric characteristics.
•The structural parameters and vibrational analysis show that fC60 is stable.•The solubility of C15H24O5 in water is improved when it is functionalized on C60.•The energy gap of fC60 show that it is ...a semiconductor material.•The modeled complex structure exhibit good nonlinear properties.•The reactivity of dihydroartemisinin is improved by using C60 as nanovector.
Density Functional Theory (DFT) calculations where performed to study the structural, electronic and nonlinear optical properties, global reactivity descriptors and the solubility of the dihydroartemisinin drug and its functionalization on C60 fullerene. The results of this study show that the geometrical parameters of the studied molecule do not change significantly after its functionalization. Furthermore, the values of the binding and reaction energies are all negative meaning that the binding of dihydroartemisinin to C60 is energetically favorable and the synthesis of our complex structure is possible. By comparing the solvation energies, we found that the functionalization of C60 fullerene improves the solubility of dihydroartemisinin in water. The gap value of functionalized fullerene is about 2.5 eV indicating that it can be considered as a semiconductor material. Finally, the functionalization considerably improves the nonlinear optical properties and the high values of first order hyperpolarizability led us to conclude that our molecules are promising material for nonlinear optical devices.
