We developed two formulations to synthesize chromium sulfide nanoparticles to analyze the effect of the chromium precursors to obtain different stoichiometries. Most works do not report samples with entangled stoichiometries. In this paper, we got a pure sample and an entangled one through slightly different formulations. There is very few information on the Raman and XPS data for chromium sulfide compounds. In this work, we support the available information through the lattice determination, indexing the diffraction patterns. The method, chemical aggregation reactions, that we utilized to prepare our material is straightforward. Besides, it is associated with short lengths of time, low costs, the number of instruments needed, precursors easy to manage and room temperature. Both formulations to elaborate the nanoparticles mentioned above differ just in the step related to the appropriate selection of the chromium source. The characterization techniques transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy, were implemented to identify our nanoparticles' chemical composition and optical properties. The first formulation leaded to an entangled composite of monoclinic Cr3S4 and rhombohedral Cr2S3 (Cr3S4/Cr2S3). The second formulation yielded a pure stoichiometry corresponding to hexagonal Cr2S3. The direct band gaps were found using the Tauc theory; the results were 2.73 eV for Cr3S4/Cr2S3 and 2.67 eV for Cr2S3. In addition, optical responses of transmission, absorption, reflection, and refractive index are presented.

It is well known that the guanidinium group in Arginine plays an important role in noncovalent interactions. However, its role is not well documented since the selection of its global minimum structure is still controversial. The main difficulties on obtaining accurate results lie on: neutral Arginine can occur in 3 forms, two of which are canonical and one is zwitterion; each form has degenerate enantiomers D- and L-; its numerous degrees of freedom make it challenging to perform a thorough study; the short-range interactions require higher levels of theory to correctly describe them. Thus, we have performed a meticulous global minimum search. We performed optimizations of the systems at the PBE0 / Def2TZVP level of theory and single point calculations at the DLPNO-CCSD(T)/Def2TZVP level with zero-point corrections at PBE0 /Def2TZVP. We also analyzed Thermal Populations and IR Spectra of the systems to fully understand Arginine's behavior. The results show the energy minima structures strongly rely on its internal nitrogen-rich groups.

In this paper, we propose to use a computational method of chaos control to simulate complex experimental spectra. This computational chaos control technique is based on the Ott–Grebogi–York (OGY) method. We chose the logistic map as the base mathematical model for the development of our work. For the numeric part, we created arbitrary precision algorithms to generate the solutions. This way, we completely eliminated any degradation of chaos from our results. These algorithms were also necessary for the proper perturbation process that the computational chaos control method requires. We control the chaos of the logistic map in two cases of Period 1 and one case of Period 2 to demonstrate that our control method works. The behavior of a complex experimental spectrum was taken and numerically simulated. The simulated spectrum was obtained by controlling the chaos of the logistic map in a variable way with the methods proposed in this work. Our results show that it is possible to simulate very complicated experimental spectra by computationally controlling the chaos of an equation unrelated to the experimental system.

Silver doped cadmium sulphide thin films were deposited on a polyethylene terephthalate flexible substrate through the chemical bath deposition method varying the silver deposition time. In this study we analyzed the absorbance in the visible range between 430 and 800 nm. The direct band gap was calculated with the Tauc method, yielding values of 2.25 to 2.46 eV. The crystallographic structure was determined by X-ray diffraction. An evolution was observed from the original hexagonal cadmium sulphide pattern to the appearance of characteristic signals of metallic silver. Scanning electron micrographs were obtained to describe the morphology of the films’s surface. Finally, the electric resistivities measured were in the range of 5.0 and 12.1 x 107 Ω cm.

Theoretical studies on conformational analysis, geometry optimizations and frequencies for citrate at the MP2/LANL2DZ level portrait it as a promising candidate for a complexing agent for cadmium (II) ion (Cd2+) and cadmium sulfide (CdS). Natural Bond Orbital (NBO) charges, Delocalization Indices, HOMO/LUMO gaps and surfaces along with absolute electronegativity values were employed to analyze the interactions among the configurations obtained. The most stable structures involved the interaction between the LUMO of Cd2+/CdS and the most dense region of the HOMO of the citrate ion.

This work focused on comparing cadmium sulphide (CdS) thin films with and without CdS silver aggregates (CdS:Ag) deposited on the surface. We report absorption and transmission responses. Using the Tauc method, we obtained direct band gap energies with values of 2.50 (CdS) and 2.49 eV (CdS:Ag). We performed a scanning electron microscope characterization at different magnifications were cluster formations with granular shapes were observed. The highest magnification of 50,000x showed silver clusters as shiny granulates, which were confirmed by microprobe elemental mapping at a magnification of 18,000x. Energy Dispersive Spectroscopy revealed that the light composition of the silver clusters was the unique difference from the CdS thin film. X-Ray Diffraction results only detected the hexagonal CdS pattern, but not that of silver. The crystallite size was of around 13 nm. A Surface-Enhanced Ramman Scattering effect was observed upon the silver coating of the CdS thin film at 293.3 cm(-1).

Molecular modelling using semiempirical methods AM1, PM3, PM5 and, MINDO as well as the Density Functional Theory method BLYP/DZVP respectively were used to calculate the struc- ture and vibrational spectra of d-glucose and d-fructose in their open chain, α-anomer and β-anomer monohydrate forms. The calculated data show that both molecules are not linear; ground state and the number for the point-group C is equal to 1. Generally, the results indicate that there are similarities in bond lengths and vibrational modes of both molecules. It is concluded that DFT could be used to study both the structural and vibrational spectra of glucose and fructose.

The goal of this research is to obtain technical information of the conformation of the CdTe/CdS junctions deposited on an ITO/Glass substrate. Their physical conditions to deposit each single layer will enable appropriate configurations to be applied on electronic devices such as alternative solar cells on silicon technology. Firstly, CdS thin films were deposited upon an ITO/Glass substrate at room temperature, with 9,000 shots at the rate of 10 shots/s, at different pressures of 20, 40, 60, 65, 70, 75 and 90 mTorr. Afterwards, CdTe thin films were grown on glass substrates all with 100,000 shoots at the rate of 10 shots/s, at the same pressure of 100 mTorr, but at different substrate temperatures: 100, 200, 300 and 400 degrees C. For CdS at the rate of 0.1 nm/s good films of 150 nm were produced in 1,500 seconds (25 min), while for CdTe at the rate of 0.0696. 0.07 nm/s, films of 696 nm in 10,000 s (166.66 min) were produced. Their morphologies, crystallite size and resistivities were also studied to propose the optimized CdTe/CdS junction for a photovoltaic application.

The main purpose of this study is to present a simplified and short process for the growth of zinc sulfide (ZnS) nanoparticles from five strategic precursors: zinc acetate, polyethyleneimine, thioacetamide, thiourea and rongalite. The first characterization is UV-vis spectrum, the next is the Tauc model to calculate the direct energy bandgap which was 3.84 eV, subsequently TEM micrographs are presented. With this technique, hexagonal crystallographic planes can be observed, fitting the PDF#83-2377 pattern. Furthermore, some particles with diameters between 25 and 29 nm which support the nanostructured nature of the compound, were found. In addition, zinc sulfide nanoparticles in suspension upon glass plane substrates were deposited through drop coating in order to observe nanoparticle agglomerations with the AFM technique. Finally, Raman dispersion and FTIR were measured and correlated.

PbS thin films were obtained using the chemical bath deposition (CBD) technique at 60 degrees C. In this paper were compared two formulations: the standard and a new one. The main result of this work is to report the new chemical formulation to build the PbS thin films, where polyethyleneimine has been used as a complexing agent. With a reaction time of 7.5 minutes we obtain a thickness of 120 nm measured with a profilometer. The structural studies, using X-ray diffraction, show that the thin film is polycrystalline and strongly oriented on the (1,1,1) plane of a cubic structure, while the thin film for the traditional formulation has a preference orientation on the (2,0,0) plane. Morphology by atomic force microscopy depicts a better flatness for the new formulation than with the traditional one. Scanning electron microscopy shows clearly in images the consistency with X-ray diffraction. Also, the optical absorption and transmission for both materials are described as a comparative in the UV-vis region. Finally to reinforce this characterization of the material, to a basic science level, XPS spectra were obtained where we can be observe only those chemical element peaks expected.

The goal of this work is to compare Lead Sulfide Thin Films grown on three different substrates: common glass a Hafnium oxide layer and a silicon dioxide layer. The morphology and cross section was characterized through SEM; XRD was utilized to chemically identify the compound and its structure; XPS was used to assure the chemical composition; and electrical measurements were performed to evaluate the resistivity. The morphology varies greatly from a smooth granulate amorphous phase to a polycrystalline clustered surface. All polycrystalline films are cubic Lead Sulfide. The clusters in these layers have crystallite sizes between 9 and 22 nm ranges. The obtained values for resistivity were 35.62 cm, and 13.50 cm for the samples with deposition time of 20 and 40 minutes, respectively.

A new semiorganic material, L-Proline-KCl, was synthesized for the first time. Its solubility an metastable zone width in double distilled water were estimated. Employing a temperature reduction method, a crystal of size 16 x 6 x 5 mm(3) was grown from aqueous solution. The cell dimensions obtained by single crystal X-ray diffraction studies reveal that the crystal belongs to the monoclinic system. UV-vis-NIR studies show that the crystal is transparent in the wavelength range of 300-1100nm. Second harmonic generation conversion efficiency found using the Kurtz an Perry method is about 0.2 times that of KDP. The thermal stability of the compound was determined by TG-DTA analyses of the specimen. The experimental results show that the crystal of L-proline-KCl is a good candidate for nonlinear optical applications, optical and thermal properties.

The interesting applications of ultrathin silica films on transition metals drove us to analyze the interactions between them. We selected only sixteen transition metals to observe a pattern and started at a molecular level to understand the principal interactions involved between them. A conformational search and a subsequent optimization of the structures, together with frequency calculations at the MP2/LANL2DZ level of theory for the metals and MP2/6-31G* for the rest of the atoms. The results show that the interactions are favorable with the transition metals we selected.

Germanate glasses have potential applications as optical fibers. Materials doped with rare earth ions are good candidates for optical, lasing, and magnetic applications. Based on the ternary system, CeO2–Na2O–GeO2 a series of six glasses were fabricated using powder fusion, and varying the Na2O content from 0 to 45 mol%, and a CeO2 content constant at 3 mol%. The glasses were analyzed by FT‐IR, Raman and X‐ray photoelectron (XPS) spectroscopies to obtain information about the glass structure, cerium oxidation's state and how it is introduced in the glass network. FT‐IR and Raman spectra revealed the presence of GeO6 and GeO4 groups as well as Q2 and Q3 units in the glasses with alkali low content. XPS spectra analysis revealed that the cerium ions were reduced from Ce4+ to Ce3+. The nonbonding to total oxygen ratio was estimated from the curve fitting of the O 1s core level spectra. Density and elastic parameters showed a nonlineal tendency in the change of the physical properties as a function of Na2O content. Finally, photoluminescence spectroscopy confirmed the presence of Ce3+ ions. The characteristic 4f → 5d electronic transitions at 360 nm were detected, when a 280 nm excitation line of pulsed laser was used as excitation source.

Starch is a natural product that has been utilized in the green synthesis of metals and semiconductors. In addition, it can aid in obtaining products with higher purity. However, the interactions involved between the metals and starch have not been studied previously. Computations have been performed at the MP2/lanl2dz level of theory for systems of Pb/PbS and the principal components of starch: amylose and amylopectin. Results show there is a favorable interaction for both polysaccharides and Pb/PbS, opening a window of possibilities of producing other chalcogenides with starch as a substrate.

PbS is a semiconductor with a great variety of applications. Our aim is to propose complexing agents to the chemical bath deposition technique to produce PbS thin films in the future. Thus, we have chosen to study the interaction between PbS and complexing agents. Previously, we have studied triethanolamine as a complexing agent. In this work, we proposed polyethyleneimine as complexing agent and compared the results with those of triethanolamine. The conformational analysis, geometry optimizations and frequencies were calculated at the same level of theory, MP2/LANL2DZ to confirm the isomer stabilities.

This work it has the goal to present a way to grow synthetic plumbonacrite thin films. Our characterization started with XRD, from where we get a hexagonal structure of the Plumbonacrite corresponding compound. The following characterization considered was the absorption spectra in the visible region and from the energy band gap was calculated Eg=1.8 eV. Our reaction conditions lead to a thickness around of 375nm of the films, measured by ellipsometry and the resistivity of these thin films was measured giving around 110 MO. Also we did X-ray Photoelectrons Spectroscopy which probed that the thin films are mainly composed by lead and oxygen. Finally we are reporting the surface morphology through AFM were it can be observed the roughness at large scale.

In this study we focus on molecular recognition towards arginine methyl ester with a cyclophane as a receptor. This macrocycle consists of two phenylene-O-phenylene units linked by two EDTA chains and carries four pendant carboxylate groups. To understand the interactions of these systems we performed a conformational search and geometry optimizations with the use of the Density Functional Theory (DFT). We decided to focus on two different scenarios. In the first one, the arginine ester and the cyclophane are not charged. In the second one, both species are ionic and the system as a whole is neutral. The computations revealed that they in fact interact favorably, where the most stable configuration is that in which cationic arginine methyl ester is extended above the cycle and interacts with the pendant deprotonated carboxylate groups.