Molecular mechanics and quantum mechanical modeling of hexane soot structure and interactions with pyrene

نویسنده

  • J. D. Kubicki
چکیده

Molecular simulations (energy minimizations and molecular dynamics) of an n-hexane soot model developed by Smith and co-workers (M. S. Akhter, A. R. Chughtai and D. M. Smith, Appl. Spectrosc., 1985, 39, 143; ref. 1) were performed. The MM+ (N. L. Allinger, J. Am. Chem. Soc., 1977, 395, 157; ref. 2) and COMPASS (H. Sun, J. Phys. Chem., 1998, 102, 7338; ref. 3) force ®elds were tested for their ability to produce realistic soot nanoparticle structure. The interaction of pyrene with the model soot was simulated. Quantum mechanical calculations on smaller soot fragments were carried out. Starting from an initial 2D structure, energy minimizations are not able to produce the observed layering within soot with either force ®eld. Results of molecular dynamics simulations indicate that the COMPASS force ®eld does a reasonably accurate job of reproducing observations of soot structure. Increasing the system size from a 683 to a 2732 atom soot model does not have a signi®cant effect on predicted structures. Neither does the addition of water molecules surrounding the soot model. Pyrene ®ts within the soot structure without disrupting the interlayer spacing. Polycyclic aromatic hydrocarbons (PAH), such as pyrene, may strongly partition into soot and have slow desorption kinetics because the PAH-soot bonding is similar to soot±soot interactions. Diffusion of PAH into soot micropores may allow the PAH to be irreversibly adsorbed and sequestered so that they partition slowly back into an aqueous phase causing dis-equilibrium between soil organic matter and porewater.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Quantum Chemical Modeling of N-(2-benzoylphenyl)oxalamate: Geometry Optimization, NMR, FMO, MEP and NBO Analysis Based on DFT Calculations

In the present work, the quantum theoretical calculations of the molecular structure of the (N-(2-benzoylphenyl) oxalamate has been investigated and are evaluated using Density Functional Theory (DFT). The geometry of the title compound was optimized by B3LYP method with 6-311+G(d) basis set. The theoretical 1H and 13C NMR chemical shift (GIAO method) values of the title compound are calculated...

متن کامل

ONIOM studies of interaction between single-walled carbon nanotube and gallates derivatives as anticancer agents

Objective(s): The novel 7-hydroxycoumarinyl gallates derivatives are detected in many pharmaceutical compounds like anticancer and antimicrobial agents. Whereas carbon nanotubes (CNTs) have been discussed for nanomedicine applications and in particular as drug delivery systems. The capability of armchair (5, 5) SWCNT -based drug delivery system in the therapy of anticancer has been investigated...

متن کامل

Investigation of Vacancy Defects on the Young’s Modulus of Carbon Nanotube Reinforced Composites in Axial Direction via a Multiscale Modeling Approach

In this article, the influence of various vacancy defects on the Young’s modulus of carbon nanotube (CNT) - reinforcement polymer composite in the axial direction is investigated via a structural model in ANSYS software. Their high strength can be affected by the presence of defects in the nanotubes used as reinforcements in practical nanocomposites. Molecular structural mechanics (MSM)/finite ...

متن کامل

Quantum Chemical Modeling of 1-(1, 3-Benzothiazol-2-yl)-3-(thiophene-5-carbonyl) thiourea: Molecular structure, NMR, FMO, MEP and NBO analysis based on DFT calculations

In the present work, the quantum theoretical calculations of the molecular structure of the 1-(1, 3-Benzothiazol-2-yl)-3-(thiophene-5-carbonyl) thiourea has been predicted and are evaluated using Density Functional Theory (DFT) in gas phase. The geometry of the title compound was optimized by B3LYP/6-311+G and B3LYP/6-311+G* methods and the experimental geometrical parameters of the title compo...

متن کامل

A quantitative study of the clustering of polycyclic aromatic hydrocarbons at high temperatures.

The clustering of polycyclic aromatic hydrocarbon (PAH) molecules is investigated in the context of soot particle inception and growth using an isotropic potential developed from the benchmark PAHAP potential. This potential is used to estimate equilibrium constants of dimerisation for five representative PAH molecules based on a statistical mechanics model. Molecular dynamics simulations are a...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2000