Adsorption of Glyoxal (CHOCHO) and Its UV Photolysis Products on the Surface of Atmospheric Ice Nanoparticles. DFT and Density Functional Tight-Binding Study

Abstract

ABSTRACT:The structures, energies, harmonic vibrational frequencies, and thermodynamic parameters of the water clusters (H 2 O) 48 , (H 2 O) 72 , and (H 2 O) 270 were calculated using the standard DFT theory (BLYP/6-31++G(d,p) for small and medium clusters) and the modern tight-binding method SCC-DFTB (DFTBA and DFTB+). The adsorption and embedding of s-cis-and s-trans-glyoxal molecules as well as its sunlight UV photolysis products (molecules CH 2 O, HCOOH, H 2 O 2 , CO, CO 2 and radicals CHO, HO, HO 2 ) on nanosized ice clusters of up to 2.5 nm in diameter were studied within the above theoretical models. The structures of adsorption complexes on different sites of ice nanoparticles, the corresponding adsorption energies and thermodynamic parameters were estimated. We found that the DFTB method is a very promising tool for the calculations of structures and energies of ice nanoparticles, when compared to both DFT and semiempirical (PM3) methods. The obtained results are discussed in relation to the possible photolysis pathways, the reaction rates in the gas phase and in the adsorbed state, and the mechanisms of glyoxal photolysis catalyzed by the ice nanoparticles in the Earth's atmosphere.

Grand canonical Monte Carlo simulation on adsorption of aniline on the ice surface

“…((S)VOCs) on the ice surface. [9,[23][24][25][39][40][41][42][43][44][45][46] The setup of simulation box was the same as that in our recent study on the adsorption of nitrobenzene on the ice surface. [39] Specifically, the simulation box was rectangular, with the X, Y, and Z edges being 100, 35.926, and 38.891 Å.…”

Na+, F–, Br–, and Cl– Adsorptions and Penetrations on an Ice Surface

“…Traditionally theoretical studies adopted limited ice surface models consisting of no more than four water molecules (see Figure a). Improved ice models, such as models using periodic boundary conditions, − nanoparticle models, as well as a quantum mechanics/molecular mechanics (QM/MM) model, have been recently used. We have also demonstrated , that the long-range electrostatic interactions and hydrogen disorders can significantly affect the chemical adsorptions on an ice surface.…”

Quantum chemical and master equation study of OH + CH2O → H2O + CHO reaction rates in supercritical CO2 environment

“…Another advantage of oxy‐combustion is the ability of CO 2 to form a supercritical fluid with a high thermal expansion coefficient, increasing the efficiency of the turbine . Combustion kinetics may alter at large concentrations of CO 2 , and theoretical chemistry can assist in studying these effects . In the first paper of this series, we investigated the effect of CO 2 on the CO + OH reactive system and found a lower activation energy pathway in which CO 2 participated covalently .…”

“…3,4 Combustion kinetics may alter at large concentrations of CO 2 , and theoretical chemistry can assist in studying these effects. [5][6][7][8] In the first paper of this series, we investigated the effect of CO 2 on the CO + OH reactive system and found a lower activation energy pathway in which CO 2 participated covalently. 9 In the following papers, we reported lowering of the activation barrier of seven other combustion reactions via van der Waals (vdW) interactions with CO 2 .…”