On the structural, electronic, and optical properties of L-histidine crystal: a DFT study.

CONTEXT: The monoclinic L-histidine crystal is critical for protein structure and function and is also found in the myelin of brain nerve cells. This study numerically examines its structural, electronic, and optical properties. Our findings indicate that the L-histidine crystal has an insulating band gap of approximately 4.38 eV. Additionally, electron and hole effective masses range between 3.92[Formula: see text]-15.33[Formula: see text] and 4.16[Formula: see text]-7.53[Formula: see text], respectively. Furthermore, our investigation suggests that the L-histidine crystal is an excellent UV collector due to its strong optical absorption activity for photon energies exceeding 3.5 eV. METHODS: To investigate the structural, electronic, and optical properties of L-histidine crystals, we used the Biovia Materials Studio software to conduct Density Functional Theory (DFT) simulations as implemented in the CASTEP code. Our DFT calculations were performed using the generalized gradient approximation (GGA) as parameterized by the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, with an additional dispersion energy correction (PBE [Formula: see text] TS) based on the model proposed by Tkatchenko and Scheffler to describe van der Waals interactions. Additionally, we employed the norm-conserving pseudopotential to treat core electrons.

Glyphosate adsorption on C60 fullerene in aqueous medium for water reservoir depollution.

The indiscriminate use of pesticides has caused several damages to the environment, in particular the pollution of water reservoirs, so that this has motivated the development of techniques to minimize its consequences. One of the main surface water pollutants is glyphosate, which is a widely used herbicide for weed control. Therefore, in this work, computational simulations were used with density functional theory and molecular dynamics to theoretically verify if C60 fullerene is capable of adsorbing glyphosate in aqueous media. As a result, we showed through the adsorption energies, molecular dynamics methods, and infrared absorption that C60 can adsorb glyphosate molecules in at least three distinct configurations, either in vacuum or in water, which theoretically indicates it as a good candidate for removal of this herbicide from water by nanotechnology techniques.