emissions from fossil fuel combustion pose a serious threat to public health and =pose the need for animproved monitoring of polycyclic aromatic hydrocarbons (pars), a major class of persistent organicpollutants. for this purpose the present study reports an investigation of the electronic structure of pyrene byuse of different chemical models we also made a comparison between different chemica...

polycyclic aromatic hydrocarbon (pah) plays an important role in the formation of combustion-generatedparticles such as soot, and their presence in atmosphere aerosols has been widely shown. the formation of five-membered rings, detected in combustion effluent, is of great interest due to their genotoxic activity.the present study reports an investigation of the electronic structure of acenapht...

Numerical modeling of global atmospheric chemical dynamics presents an enormous challenge, associated with simulating hundreds of chemical species with time scales varying from milliseconds to years. Here we present an algorithm that provides a significant reduction in computational cost. Because most of the fast reactants and their quickly decomposing reaction products are localized near emiss...

We report the first detection of triply-deuterated methanol, with 12 observed transitions, towards the low-mass protostar IRAS 16293−2422, as well as multifrequency observations of CH3OH, used to derive the column density of the main isotopomer CH3OH. The derived fractionation ratio [CD3OH]/[CH3OH] averaged on a 10′′ beam is 1.4%. Together with previous CH2DOH and CHD2OH observations, the prese...

Coupled systems can exhibit an unusual kind of multistability, namely, the coexistence of infinitely many attractors for a given set of parameters. This extreme multistability is demonstrated to occur in coupled chemical model systems with various types of coupling. We show that the appearance of extreme multistability is associated with the emergence of a conserved quantity in the long-term li...

We study two chemical models for pattern formation in growing plant tips. For hemisphere radius and parameter values together optimal for spherical surface harmonic patterns of index l = 3, the Brusselator model gives an 84% probability of dichotomous branching pattern and 16% of annular pattern, while the hyperchirality model gives 88% probability of dichotomous branching and 12% of annular pa...

We introduce and investigate a chemical model based on perturbative corrections to the product of singlet-type strongly orthogonal geminals wave function. Two specific points are addressed (i) Overall chemical accuracy of such a model with perturbative corrections at a leading order; (ii) Quality of strong orthogonality approximation of geminals in diverse chemical systems. We use the Epstein-N...

Chiral hypercycle replicators (first-order autocatalysis together with mutual cross-catalysis) formed from achiral or racemizing resources may lead to spontaneous mirror symmetry breaking (SMSB) without the need for additional heterochiral inhibition reactions, such as those of the Frank-like models, which are an obstacle for the emergence of evolutionary selection properties. The results indic...

We analyze a quasi-chemical model for bacterial growth in the context of a parameter estimation problem using available experimental data sets. For many of the data sets the dynamics are simple and we show that the quasi-chemical model (QCM) is over parameterized in these cases. This results in larger uncertainty in the estimated parameters and is some cases instability in the inverse problem. ...