Thermochemical properties of polycyclic aromatic hydrocarbons (PAH) from G3MP2B3 calculations.
نویسندگان
چکیده
In this article, we present a new database of thermodynamic properties for polycyclic aromatic hydrocarbons (PAH). These large aromatic species are formed in very rich premixed flames and in diffusion flames as part of the gas-phase chemistry. PAH are commonly assumed to be the intermediates leading to soot formation. Therefore, accurate prediction of their thermodynamic properties is required for modeling soot formation. The present database consists of 46 species ranging from benzene (C6H6) to coronene (C24H12) and includes all the species usually present in chemical mechanisms for soot formation. Geometric molecular structures are optimized at the B3LYP/6-31++G(d,p) level of theory. Heat capacity, entropy, and energy content are calculated from these optimized structures. Corrections for hindered rotor are applied on the basis of torsional potentials obtained from second-order Møller-Plesset perturbation (MP2) and Dunning's consistent basis sets (cc-pVDZ). Enthalpies of formation are calculated using the mixed G3MP2//B3 method. Finally, a group correction is applied to account for systematic errors in the G3MP2//B3 computations. The thermodynamic properties for all species are available in NASA polynomial form at the following address: http://www.stanford.edu/group/pitsch/.
منابع مشابه
Determination of Polycyclic Aromatic Hydrocarbons in Ambient Urban Air
Polycyclic aromatic hydrocarbons (PAHS) have been determined in the atmosphere of Isfahan, Iran. Airborne particulate matter was sampled using a high-volume air sampler at roof-top level (~6m). Extraction of PAHS from airborne particulate matter has been performed using SFE system and the relationship between the extraction temperature and the recovery of PAHS</su...
متن کاملFirst-Principles Prediction of Enthalpies of Formation for Polycyclic Aromatic Hydrocarbons and Derivatives.
In this article, the first-principles prediction of enthalpies of formation is demonstrated for 669 polycyclic aromatic hydrocarbon (PAH) compounds and a number of related functionalized molecules. It is shown that by extrapolating density functional theory calculations to a large basis set limit and then applying a group based correction scheme that good results may be obtained. Specifically, ...
متن کاملSynthesis and electronic properties of polycyclic aromatic hydrocarbons doped with phosphorus and sulfur.
In this work, we report on the synthesis of polyaromatic hydrocarbons containing phosphole and thiophene rings at the edge. The ring-closure reactions have been investigated by theoretical calculations. The optical and electrochemical properties and density functional theory calculations showed that the properties depend on the relative position of these five membered rings in the PAH structure.
متن کاملBiodegradation of Polycyclic Aromatic Hydrocarbons by Aerobic Mixed Bacterial Culture Isolated from Hydrocarbon Polluted Soils
In this study, the degradation potential of five polycyclic aromatic hydrocarbons (PAHs) by aerobic mixed bacterial cultures was investigated. Microorganisms were isolated from hydrocarbon contaminated soils of Shadegan wetland located in southwest of Iran. The degradation experiments were conducted in liquid cultures. PAH or PAHs concentration was 100 mg/L at the beginning of degradation e...
متن کاملAccurate and efficient method for predicting thermochemistry of polycyclic aromatic hydrocarbons - bond-centered group additivity.
A self-consistent estimation method for the thermochemical properties of polycyclic aromatic hydrocarbons (PAH) is presented. This method is based on enthalpies of formation (DeltaHf(degrees), entropies (S(degrees)298, and heat capacities (C(degrees)p obtained from B3LYP/6-31G(d) calculations of the total energies and frequencies for 139 PAHs, including C(60) and C(70) fullerenes. The enthalpie...
متن کاملذخیره 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 ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The journal of physical chemistry. A
دوره 111 28 شماره
صفحات -
تاریخ انتشار 2007