Quantum mechanical investigations of mechanical and thermodynamic properties of SiC and ZrO ceramics.

The mechanical and thermodynamic properties of β and α structures of SiC and also monoclinic and cubic structures of ZrO have been considered via first-principles investigations based on the ultrasoft pseudopotential plane-wave DFT method. The calculated lattice constants, elastic constants, and mechanical properties of all the structures are in agreement with earlier DFT works and experimental reports, which show that the applied method is applicable. Also, the pressure-dependency performances of thermodynamic and mechanical properties of cubic structures of ZrO and SiC, from 0 to 50 Gpa pressure, have been studied.

Quantum mechanical studies of the adsorption of Remdesivir, as an effective drug for treatment of COVID-19, on the surface of pristine, COOH-functionalized and S-, Si- and Al- doped carbon nanotubes.

Remdesivir has been recognized as an important medicine in the control of COVID-19 illness. Since carbon nanotubes were considered in the design of novel drug delivery vehicles, the interaction between simple CNT, functionalized CNT by carboxylic group and S-, Al-, and Si-doped CNT and Remdesivir drug were studied using density functional theory (DFT) and time dependent DFT (TDDFT) calculations. The results of this work show that the Si-doped CNT is the best drug delivery system for Remdesivir due to its better electronic, energetic, adsorption and thermodynamic properties.

A quantum study on novel azo-dyes containing a fullerene C60 unit as a smart material for optoelectronic applications.

Quantum chemical calculations of some novel azo-dyes containing a fullerene C60 unit as a smart material have been carried out with the aims to determine their cis and trans electronic properties and to describe the change of their quantum parameters as a result of the trans/cis isomerization of these molecules. The effects of electron-withdrawing or electron-releasing groups on the R-position of these molecules on electronic, optical, spectroscopic, and other properties of these molecules have been considered with DFT and TDDFT calculations. The obtained results of the calculations show that compounds "b" and "c" with the strongest electron-releasing groups in the R-position of these molecules, particularly the trans isomers of these compounds, with higher chemical softness, higher electrophilicity index, higher thermodynamic properties, and higher charge transfer values, have the better electronic and optical properties and therefore the better chemical reactivity compared to the other compounds.

Quantum mechanical simulation of Chloroquine drug interaction with C60 fullerene for treatment of COVID-19.

Chloroquine (CQ) has been reported as an effective drug in the control of COVID-19 infection. Since C60 fullerene has been considered as a drug delivery system, the interaction between pristine fullerene and chloroquine drug and also the interaction between B, Al, Si doped fullerene and chloroquine drug have been investigated based on the density functional theory calculations. The results of this study show that the doped fullerene, especially Al and Si doped fullerene could be the better drug delivery vehicles for chloroquine drug because of their relatively better energetic and electronic properties with chloroquine.

Deep analysis of N-cadherin/ADH-1 interaction: a computational survey.

Due to the considerable role of N-cadherin in cancer metastasis, tumor growth, and progression, inhibition of this protein has been highly regarded in recent years. Although ADH-1 has been known as an appropriate inhibitor of N-cadherin in clinical trials, its chemical nature and binding mode with N-cadherin have not been precisely specified yet. Accordingly, in this study, quantum mechanics calculations were used to investigate the chemical nature of ADH-1.

Density functional theory study of structural and electronic properties of trans and cis structures of thiothixene as a nano-drug.

The geometrical structure, electronic and optical properties, electronic absorption spectra, vibrational frequencies, natural charge distribution, MEP analysis and thermodynamic properties of the trans and cis structures of the drug thiothixene were investigated using density functional theory (DFT) and time-dependent DFT (TDDFT) methods with the B3LYP hybrid functional and 6-311 + G(d,p) basis set. The results of the calculations demonstrate that the cis structure of thiothixene has appropriate quantum properties that can act as an active medicine. The relative energies of trans and cis structures of thiothixene shows that the cis structure is more stable than the trans structure, with a small energy difference.

The polythiophene molecular segment as a sensor model for H2O, HCN, NH3, SO3, and H2S: a density functional theory study.

Studying the interaction of some atmospheric gases (H2O, HCN, NH3, SO3 and H2S) with 3PT oligomers is important in the development of polymeric sensors for gas detection. In the present study, we studied the relaxed geometries, interaction energies, charge analysis, HOMO-LUMO orbital analysis, and UV-vis spectra of all interacted systems using first-principles density functional theory (DFT). All these analyses indicated the potential of polythiophene as an inexpensive polymeric sensor for the analytes mentioned.

Density functional theory study of new azo dyes with different π-spacers for dye-sensitized solar cells.

Some of new azo-based metal-free dyes with different π-conjugation spacers, such as carbazole, fluorene, pyrrole, thiophene, furan and thiazole, have been investigated with density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. Theoretical calculations allow us to quantify factors such as light harvesting efficiency (LHE), electron injection driving force (ΔG(inject)) and the weight of the LUMO orbital on the carboxylic group (QLUMO) related to the short-circuit photocurrent density (Jsc), and to evaluate both charge recombination between the semiconductor conduction band electrons and the oxidized dyes and/or electrolyte, and also the shift of the conduction band of the semiconductor as a result of the adsorption of the dyes onto the semiconductor surface, associated with the open-circuit photovoltage (Voc). According to the results, we could predict that how the π-conjugation spacers influence the Jsc as well as the Voc of DSSCs.