Search

The chlorine-initiated reaction mechanism of ethyl formate in the atmosphere was investigated using the density functional theory method. The geometry parameters and frequencies of all of the stationary points were calculated at the B3LYP/ 6-31G(d, p) level. The single-point energy calculations were carried out at different levels, including MP2/6-31G(d), MP2/6-311++G(d, p), and CCSD(T)/6-31G(d). A detailed oxidation mechanism is provided and discussed. Present results show that α-ester rearrangement reaction and the [O.sub.2] direct abstraction from IM6 (HC(O)OCH(O)C[H.sub.3]) are the more favorable pathway and are competitive. The 1,4-H shift isomerization of IM6 proved to be feasible under general atmospheric conditions. The decomposition of IM18 (C[H.sub.3]C[H.sub.2]OC(O)O) is favorable both thermodynamically and kinetically. Canonical variational transition theory with small-curvature tunneling correction was employed to predict the rate constants. The overall rate constant of ethyl formate at 298 K is 8.63 x [10.sup.-12] [cm.sup.3] [molecule.sup.-1] [s.sup.-1]. The Arrhenius equations of rate constants at the temperature range of 200-380 K were fitted. Key words: ethyl formate, chlorine atom, reaction mechanism, kinetic parameters. Resume: Le mecanisme de reaction du formiate d'ethyle initie par le chlore dans l'atmosphere a ete etudie a l'aide de la theorie de la fonctionnelle de la densite. Les parametres geometriques et les frequences de tous les points stationnaires au niveau B3LYP/6-31G(d, p) ont ete calcules. Les calculs d'energie en un point fixe ont ete effectues a differents niveaux, parmi lesquels MP2/6-31G(d), MP2/6-311++G(d,p) et CCSD(T)/6-31G(d). Un mecanisme d'oxydation est expose et etudie de maniere approfondie. Les resultats actuels montrent que la reaction de rearrangement de l'[alfa]-ester et l'abstraction directe d'[O.sub.2] du compose IM6 (HC(O)OCH(O)C[H.sub.3]) sont les voies les plus favorisees et sontcompetitives. Ilest demontre que l'isomerisation du compose IM6 par le chngement 1,4-H est realisable sous conditions atmospheriques normales. La decomposition d'IM18 (C[H.sub.3]C[H.sub.2]OC(O)O) est thermodynamiquement et cinetiquement favorisee. La theorie de l'etat de transition variationnel canonique associee a une correction de l'effet tunnel avec faible courbure a ete employee pour predire les constantes de vitesse de reaction. Le formiate d'ethyle presente une constante de vitesse globale de 8,63 x [10.sup.-12] [cm.sup.3] [molecule.sup.-1] [s.sup.-1] a 298 K. Les equations d'Arrhenius ont permis de determiner les differentes constantes de vitesse dans l'intervalle de temperature compris entre 200 et 380 K. [Traduit par la Redaction] Mots-cles: formiate d'ethyle, atome de chlore, mecanisme reactionnel, parametres cinetiques., Introduction Ethyl formate (EF) (HC(O)OC[H.sub.2]C[H.sub.3]) is an important saturated ester and can be produced by many fruits and vegetables. Moreover, it occurs naturally in a variety of products, including essential [...] more...

Melting phase relations of a model chloride- and carbonate-bearing eclogite have been studied at 7.0-10.5 GPa and 1200-1675[degrees]C. The mineral assemblage coexisting with partial melts is garnet, omphacite, kyanite, and coesite or stishovite. At temperatures of 1200-1400[degrees]C, the partial melt has an Si[O.sub.2]-poor, Cl-bearing carbonatite composition. With increasing temperature, it becomes progressively Si[O.sub.2] rich, and at temperatures of 1500-1700[degrees]C contains as much as 53 wt% Si[O.sub.2]. The compositions of the melts are comparable with those of silicic end members of inclusions in fibrous and/or cloudy diamonds worldwide, implying that they may be produced via chemical reactions of alkalic chloride-carbonate liquids with mantle eclogites. Our experiments reproduced the trends of the compositional variations of the fluid or melt inclusions within eclogitic diamonds, and thus suggest a reliable model for their origin. doi: 10.1130/G31325.1 more...

High level ab initio calculations at the MP2/cc-pVTZ, CCSD(T)/ cc-pVTZ, and CASSCF(6,6)/cc-pVTZ levels were performed to investigate geometries and energies of superelectrophilic diprotonated, and dimethylated molecular chlorine ([Cl.sub.2]) and bromine ([Br.sub.2]) dications. Diprotonated chlorine and diprotonated bromine dications 3a and 6a, respectively, were found to be lowest energy minima. The isomeric dications, 3b and 6b, are also minima on the potential energy surfaces but they are significantly less stable than the structures 3a and 6a by 33.6 and 30.9 kcal/mol, respectively. On the basis of computed G2 energies, proton affinities and related thermodynamic parameters were also calculated. Dications 3a and 6a have substantial kinetic barriers for deprotonation. Their homolytic dissociation are however facile. Dimethylated molecular chlorine and bromine dications 3g and 6g, respectively, were also found to be global energy minima. These vicinal dihalonium or the corresponding protosolvated species are expected to form either in the superacidic media or in the gas phase. ab initio | halonium | superacid | gas phase doi/ 10.1073/pnas.1001603107 more...

A real-time estimation of water distribution system state variables such as nodal pressures and chlorine concentrations can lead to savings in time and money and provide better customer service. While a good knowledge of nodal demands is prerequisite for pressure and water quality prediction, little effort has been placed in real-time demand estimation. This study presents a real-time demand estimation method using field measurement provided by supervisory control and data acquisition systems. For real-time demand estimation, a recursive state estimator based on weighted least-squares scheme and Kalman filter are applied. Furthermore, based on estimated demands, real-time nodal pressures and chlorine concentrations are predicted. The uncertainties in demand estimates and predicted state variables are quantified in terms of confidence limits. The approximate methods such as first-order second-moment analysis and Latin hypercube sampling are used for uncertainty quantification and verified by Monte Carlo simulation. Application to a real network with synthetically generated data gives good demand estimations and reliable predictions of nodal pressure and chlorine concentration. Alternative measurement data sets are compared to assess the value of measurement types for demand estimation. With the defined measurement error magnitudes, pipe flow data are significantly more important than pressure head measurements in estimating demands with a high degree of confidence. DOI: 10.1061/(ASCE)HY.1943-7900.0000086 CE Database subject headings: Estimation; Least squares method; Water distribution systems; Uncertainty principles; Limit analysis. more...

A quantum chemistry analysis of the elementary vapor-phase reaction between chlorine atoms and formaldehyde is presented. The reaction is characterized by a low electronic barrier.

Salt and water absorption and secretion across the airway epithelium are important for maintaining the thin film of liquid lining the surface of the airway epithelium. Movement of Cl across the apical membrane involves the CFTR Cl channel; however, conductive pathways for Cl movement across the basolateral membrane have been little studied. Here, we determined the regulation and single-channel properties of the Cl conductance ([G.sub.Cl]) in airway surface epithelia using epithelial cultures from human or bovine trachea and freshly isolated ciliated cells from the human nasal epithelium. In Ussing chamber studies, a swelling-activated basolateral [G.sub.Cl] was found, which was further stimulated by forskolin and blocked by N-phenylanthranilic acid (DPC) = sucrose > flufenamic acid = niflumic acid = glibenclamide > Cd[Cl.sub.2] = 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) = DIDS = Zn[Cl.sub.2] > tamoxifen > 4,4'-dinitro-2,2'-stilbene-disulfonate disodium salt (DNDS). In whole cell patch-clamp experiments, three types of [G.sub.Cl] were identified: 1) a voltage-activated, DIDS- (but not Cd-) blockable and osmosensitive [G.sub.Cl]; 2) an inwardly rectifying, hyperpolarization-activated and Cd-sensitive [G.sub.Cl]; and 3) a forskolin-activated, linear [G.sub.Cl], which was insensitive to Cd and DIDS. In cell-attached patch-clamp recordings, the basolateral pole of isolated ciliated cells expressed three types of Cl channels: 1) an outwardly rectifying, swelling-activated Cl channel; 2) a strongly inwardly rectifying Cl channel; and 3) a forskolin-activated, low-conductance channel. We propose that, depending on the driving force for Cl across the apical membrane, basolateral Cl channels confine [Cl.sup.-] secretion or support transcellular [Cl.sup.-] absorption. airway epithelium; ion transport; absorption; secretion; chloride channels; basolateral membrane doi: 10.1152/ajplung.00032.2007 more...

[Cl.sup.-] currents were observed under whole cell clamp conditions in cells of the rat cortical collecting duct (CCD), connecting tubule (CNT), and thick ascending limb of Henle's loop (TALH). These currents were much larger in intercalated cells compared with principal cells of the CCD and were also larger in the TALH and in the CNT compared with the CCD. The conductance had no strong voltage dependence, and steady-state currents were similar in inward and outward directions with similar [Cl.sup.-] concentrations on both sides of the membrane. Current transients were observed, particularly at low [Cl.sup.-] concentrations, which could be explained by solute depletion and concentration in fluid layers next to the membrane. The currents had a remarkable selectivity among anions. Among halides, [Br.sup.-] and [F.sup.-] conductances were only 15% of that of [Cl.sup.-], and [I.sup.-] conductance was immeasurably small. [SCN.sup.-] and [OCN.sup.-] conductances were ~50%, and aspartate, glutamate, and methanesulfonate conductance was ~5% that of [Cl.sup.-]. No conductance could be measured for any other anion tested, including N[O.sub.3.sup.-], HC[O.sub.3.sup.-], formate, acetate, or isethionate; N[O.sub.3.sup.-] and [I.sup.-] appeared to block the channels weakly. Conductances were diminished by lowering the extracellular pH to 6.4. The properties of the conductance fit best with those of the cloned renal anion channel ClC-K2 and likely reflect the basolateral [Cl.sup.-] conductances of the cells of these nephron segments. ClC-K2; anion selectivity; basolateral membrane; intercalated cells more...

Characterizing the interaction of hydrogen chloride (HCI) with polar stratospheric cloud ice particles is essential for understanding the processes responsible for ozone depletion. We studied the interaction of gas-phase HCI with ice between 243 and 186 K by using (i) ellipsometry to monitor the ice surface and (ii) coated-wall flow tube experiments, both with chemical ionization mass spectrometry detection of the gas phase. We show that trace amounts of HCI induce formation of a disordered region, or quasi-liquid layer, at the ice surface at stratospheric temperatures. We also show that surface disordering enhances the chlorine activation reaction of HCI with chlorine nitrate (CION[O.sub.2]) and also enhances acetic acid (C[H.sub.3]COOH) adsorption. These results impact our understanding of the chemistry and physics of ice particles in the atmosphere. chlorine activation | ice chemistry | ozone depletion | stratosphere more...

Zn, an essential micronutrient and second most abundant trace element in cell and tissues, reduces stool output when administered to children with acute diarrhea. The mechanism by which Zn improves diarrhea is not known but could result from stimulating Na absorption and/or inhibiting anion secretion. The aim of this study was to investigate the direct effect of Zn on intestinal epithelial ion absorption and secretion. Rat ileum was partially stripped of serosal and muscle layers, and the mucosa was mounted in lucite chambers. Potential difference and short-circuit current were measured by conventional current-voltage clamp method. [sup.86]Rb efflux and uptake were assessed for serosal K channel and Na-K-2Cl cotransport activity, respectively. Efflux experiments were performed in isolated cells preloaded with [sup.86]Rb in the presence of ouabain and bumetanide, whereas uptake experiments were performed in low-Cl isotonic buffer containing Ba and ouabain. Neither mucosal nor serosal Zn affected glucose-stimulated Na absorption. In contrast, forskolin-induced Cl secretion was markedly reduced by serosal but not mucosal addition of Zn. Zn also substantially reversed the increase in Cl secretion induced by 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) with half-maximal inhibitory concentration of 0.43 mM. In contrast, serosal Zn did not alter Cl secretion stimulated by carbachol, a Ca-dependent agonist. Zn inhibited 8-BrcAMP-stimulated [sup.86]Rb efflux but not carbachol-stimulated [sup.86]Rb efflux. Zn had no effect on bumetanide-sensitive [sup.86]Rb uptake, Na-K-ATPase, or CFTR. We conclude from these studies that Zn inhibits cAMP-induced Cl secretion by blocking basolateral membrane K channels. enterocyte; [sup.86]Rb efflux; [sup.86]Rb uptake; K-channel inhibitors more...

Single molecules detected through the phosphorescence emission of their triplet states, and the emission of the triplet state of single molecules of PtOBCP and Ru(dpp)3Cl(sub 2) are reported. Each molecule was found to have its own characteristic quenching rate by oxygen, and the distribution of the rates was measured for Ru(dpp)3Cl(sub 2) on a quartz surface. more...

The equilibrium isotope effect (EIE) for oxidative addition of H2 and D2 to Ir(PMe2Ph)(sub 2)(CO)Cl is measured over a large temperature range, demonstrating that the inverse (< 1) EIE previously observed at ambient temperature becomes normal (> 1) at high temperature (> 90 degrees Celsius). The occurrence of a maximum in the EIE is the result of the entropy term being temperature dependent. more...

The consequences of the aromatic consistency at the speed of [1,5]-hydrogen moves in a sequence of carbo-and heterocyclic dihydroaromatic compounds which were approximately calculated by the B3LYP divided by 6-31G. The Marcus theory can be effectively used for different pericyclic shifts like the [1,5]-shifts that comprise of the transmission of chlorine and methyl. more...

An endocyclic restriction test for acid-catalyzed transfer of chlorine from a protonated chloromine to an aromatic ring provides data that are consistent with a transition structure with a large bond angle between the entering and leaving groups around chlorine. The results rule a mechanism that has an oblique angle between the entering and leaving groups. more...

The Claisen rearrangements of chorismate in water and at the active site of E. coli chorismate mutase are compared. Seven diaxial conformers are identified, from a total of 33 ns molecular simulation of chorismate in water solvent. more...

The Fourier transform infrared spectroscopy is used to investigate the adsorption and photoreactions of CH2Cl2 on powdered titanium oxide. The procedures used in the study are explained.

Epithelial cells of the epididymis and vas deferens establish an optimum luminal environment in which spermatozoa mature and are stored. This is achieved by active transepithelial transport of various ions including [Cl.sup.-] and [H.sup.+]. We investigated the localization of three closely related members of the ClC family, ClC-3, ClC-4, and ClC-5, in the epididymis and vas deferens. RT-PCR using mRNA isolated by laser capture microdissection (LCM)-detected ClC-3 and ClC-5 transcripts but did not detect any ClC-4specific transcript. Western blot and immunofluorescence analysis demonstrated that ClC-3 and ClC-5 proteins are present in all regions of the epididymis and in the vas deferens. ClC-5 is expressed exclusively in [H.sup.+]-ATPase-rich cells (narrow and clear cells). Confocal microscopy showed that ClC-5 partially colocalizes with the [H.sup.+]-ATPase in the subapical pole of clear cells. ClC-3 is strongly expressed in the apical membrane of principal cells of the caput epididymidis and the vas deferens and is less abundant in principal cells of the body and cauda epididymidis. These findings are consistent with a potential role for ClC-3 in transepithelial chloride transport by principal cells and for ClC-5 in the acidification of [H.sup.+]-ATPase-containing vesicles in narrow and clear cells. ClC-5 might facilitate endosome trafficking in the epididymis, as has been proposed in the kidney. chloride channels, vacuolar [H.sup.+]-ATPase, principal cells, clear cells; laser capture microdissection more...

The study of CL(super -)(H2O)(sub n) (n = 1-6) clusters using ab initio calculations is presented. It is found that the structures of the various Cl(super -)(H2O)n isormers differed considerably from those of the corresponding F(super -)(H2O)n isomers for n=2 and 4-6, and especially so for n=6. more...

A study demonstrates that stable radicals can inhibit back electron transfer by enhancing intersystem crossing of a singlet ion pair into its triplet state. The phenomenon is demonstrated on a series of dyads between porphyrin/chlorin and fullerene C60. more...

Observations of the Io plasma torus and neutral clouds indicate that the extended ionian atmosphere must contain sodium, potassium, and chlorine in, atomic and/or molecular form. Models that consider sublimation of pure sulfur dioxide frost as the sole mechanism for generating an atmosphere on Io cannot explain the presence of alkali and halogen species in the atmosphere--active volcanoes or surface sputtering must also be considered, or the alkali and halide species must be discharged along with the S[O.sub.2] as the frost sublimates. To determine how volcanic outgassing can affect the chemistry of Io's atmosphere, we have developed a one-dimensional photochemical model in which active volcanoes release a rich suite of S-, O-, Na-, K-, and Cl-bearing vapor and in which photolysis, chemical reactions, condensation, and vertical eddy and molecular diffusion affect the subsequent evolution of the volcanic gases. Observations of Pele plume constituents, along with thermochemical equilibrium calculations of the composition of volcanic gases exsolved from high-temperature silicate magmas on Io, are used to constrain the composition of the volcanic vapor. We find that NaCl, Na, Cl, KCl, and K will be the dominant alkali and chlorine gases in atmospheres generated from Pele-like plume eruptions on Io. Although the relative abundances of these species will depend on uncertain model parameters and initial conditions, these five species remain dominant for a wide variety of realistic conditions. Other sodium and chlorine molecules such as NaS, NaO, [Na.sub.2], NA[S.sub.2], Na[O.sub.2], NaOS, NaS[O.sub.2], SCl, ClO, [Cl.sub.2], [S.sub.2]Cl, and S[O.sub.2][Cl.sub.2] will be only minor constituents in the ionian atmosphere because of their low volcanic emission rates and their efficient photochemical destruction mechanisms. Our modeling has implications for the general appearance, properties, and variability of the neutral sodium clouds and jets observed near Io. The neutral NaCl molecules present at high altitudes in atmospheres generated by active volcanoes might provide the Na[X.sup.+] ion needed to help explain the morphology of the high-velocity sodium 'stream' feature observed near Io. Key Words: Io; photochemistry; atmospheres, composition; volcanism; geochemistry; alkalis; halogens. more...

Research is presented concerning the use of Response Surface Methodology to investigate the effect of washing spinach,which had been freshly cut, with aqueous chlorine solutions. The reduction in microbial contamination is discussed. more...

Research has been conducted on the pentadentate ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1). The synthesis of this ligand has been performed via the high dilution cyclization of 1-oxa-4,8-diazacyclododecane with 1,3-bis(alpha-chloroacetamido)propane and the reduction of the diamide intermediate. more...

The photochemical synthesis of the benzonaphthyridinones from the 2-halo-N-pyridinylbenzamide photoreaction has been conducted. The reaction mechanism based on the preparative, kinetic and laser flash photolysis studies is discussed. more...

Femtosecond transient absorption spectroscopy was used to study the photochemistry of chlorine dioxide in aqueous solution.

Measurements of Cl2 and Cl number densities in chlorine transformer-coupled plasmas are presented.

Research has been conducted on the biphenyl dioxygenase from Burkholderia sp. strain LB400. The effect of the chlorine substituents on the catalysis has been investigated.

Research has been conducted on the human Cl (super)- /HCO (sub)3 (super)- anion exchanger (AE1). The binding site of AE1 has been examined.

Research has been conducted on the N (sub)2 H (sub)5 (super)+ oxidations by Br (sub)2, Cl (sub)2 and BrCl. The use of stopped-flow and pulsed-accelerated-flow methods is discussed.

Research has been conducted on the secretory Na (super)+ - K (super)+ - 2Cl (super)- cotransporter in rat parotid plasma membranes. The use of chemical cross-linker [3,3'-dithiobis-(sulfosuccinimidyl propionate)] is discussed. more...

Two new chlorine structures on the (111) face of silver are reported.

Research has been conducted on the site-specific mutagenesis. The acidic side chain function in nucleotide binding and in H (super)+ and Cl (super)- transport has been investigated.

Oxidation of a series of metal complexes by aqueous chlorine yields a linear free energy relationship relating k(sub et) to E degrees, which is consistent with an outer-sphere electron-transfer mechanism. The data establishes lower limits to E degrees for the Cl2/Cl(sub 2)(super -) redox couple and for [Ru(bpy)(sub 3)](super 2+) the thermal rates are uncompetitive with the photochemical rates. more...

Research has been conducted on the lipoprotein(a) [Lp(a)]. The effect of NaCl and 6-aminohexanoic acid on the Lp(a) structure has been investigated.

Research has been conducted on the diruthenium and dirhodium complexes. The nature of the metal-axial ligand interaction has been investigated.

The operation of the phosphoric acid coated microwave discharge tube of the very low-pressure reactor system produces a low, permanent H atom inlet flow. There are very good mass balances between the Cl2 consumption and both HCl and Cl product formation. more...

An analysis of how the dynamics and spectroscopy of ClHCl change as the number of argon atoms rises from zero to five is presented. As the number of argon atoms is increased, the amount of configuration space available for the hydrogen atom to orbit around the chlorine atoms is significantly reduced. more...

Research has been conducted on the reaction of Cl (sub)2 with the dinuclear [RuCl (sub)2 (dppb)] (sub)2 (mu-dppb) in MeOH. The use of X-ray diffraction is discussed.

Langmuir probe analysis and microwave interferometry were used in measuring the time dependencies of the electron, positive and negative ion densities and electron temperature in chlorine plasmas. It was observed that the average electron density was low when the average power was also low and the degree of modulation large. The positive ion density was modulated by a factor of 2 under the same conditions. However, when the average input power increases to 500 W, the modulation decreases significantly at low pressures. more...

Different FTIR smog chamber techniques have been used to investigate the products of Cl atom initiated oxidation of C (sub)2 Cl (sub)4 in the presence and absence of NO (sub)x. Atmospheric chemistry of C (sub)2 Cl (sub)4 has been discussed. more...

Research has been conducted on the transition cluster chemistry compounds. The crystal structure of these compounds reveal that they consist of different hexanuclear cluster cations and cluster anions. more...

Actinometry has been used as the basis of a successful sensor for controlling fluorine concentration in fluorocarbon plasmas commonly employed in etching. An analogous sensor would be useful for chlorine plasmas as well. One problem with actinometry in [Cl.sub.2] plasmas is that excitation can occur by electron impact dissociation and by dissociative attachment, leading to potential ambiguity between the intensity of observed chlorine emission in a plasma and the actual concentration of chlorine. On the basis of a simple model, this paper analyzes the consequences of the dissociative excitation pathway on the accuracy of the estimation and control of chlorine concentration via actinometry. When the contribution of the dissociative excitation pathway is known, it is shown that asymptotic observer theory can be used to improve the accuracy of the estimation of chlorine concentration. more...

Research was conducted to examine the characteristics of SiO2 film and the Si/SiO2 interface formed by remote plasma enhanced chemical vapor deposition with the addition of chlorine into SiH4-N2O. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, ellipsometry, secondary ion mass spectroscopy, electron spin resonance, transmission electron microscopy and atomic force microscopy were used to characterize the SiO2 films deposited with the chlorine addition. more...

A study relating to OH reactions with ClO presents results from the study of the temperature dependence of the rate coefficient for the reactions OH + ClO -- HO2 + Cl and OH + ClO -- HCl + O2. These reactions were examined under pseudo-first-order conditions in OH. ClO was generated via the reaction Cl + O3 -- ClO + O2 under conditions where excess O3 was present, or where O3 was completely depleted during ClO production. Experimental methodology is presented. more...

A study of the Cl atom initiated oxidation of CF3OCH3 in 700 Torr of N2/O2 at 296 K using a smog chamber/Fourier transform infrared spectroscopy approach showed that k(Cl + CF3OCH3) = (1.4 +/- 0.2) x 10(super -13) and k(Cl + CF3OC(O)H) = (9.8 +/- 1.2) x 10(super -15) cm3 molecule(super -1) s(super -1). The only loss mechanism of the CF3OCH2O* radical was reaction with O2 at 700 Torr of N2/O2 diluent at 296 K. The thermal decomposition rate of CF3OC(O)O2NO2 is (2.3 +/- 0.1) x 10(super -4) s(super -1) in 700 Torr of N2 at 295.8 K. The reaction of CF3OC(O)O2 radicals with HO2 radicals affords CF3OC(O)H in (80 +/- 11)% yield. more...

Research was conducted to examine the ab initio, density functional and semiempirical SCF calculations for Al2Cl6, Alcl3, AlCl4-, Al2Cl7-, AlCl2+, HAlCl4, HAlCl3+, HAlcl5- and HAl2Cl8. The objective was to assess the importance of the species to ambient-temperature melt studies in the light of the Delta-G-degrees and K values for key reactions. Equilibrium constants and thermodynamic information at 298 K are described for 22 reactions using measurements at the best level. more...

Ion energy distributions, relative ion intensities and absolute total ion current densities were examined at the grounded electrode of an inductively coupled Gaseous Electronics Conference radio-frequency reference cell for discharges produced in pure argon, nitrogen, oxygen and chlorine, and in mixtures of argon with N2, O2 and Cl2. Measured current densities were substantially greater for pure argon and for mixtures containing argon than for pure N2, O2 and Cl2. more...

The very low pressure reactor procedure was used in determining the absolute reaction rate of Cl atoms with chloroiodomethane (CH2ClI) in the gas phase at the temperature range 373 to 363 K. The reaction was done in a cylindrical Knudsen type flow reactor connected through a variable exit aperture to the first stage of a differentially pumped system. The Cl atoms were generated by flowing a mixture of 5% Cl2 in helium through a quartz tube which is coated with a thin film of phosphoric acid. The absolute reaction rate was found to be 3.13 plus/minus 0.27 X 10 raised to the negative 11th power cubic cm per molecule per second. more...

Quantum mechanical cumulative reaction probabilities (CRPs) for the reaction Cl + H2 -> HCl + H and its reverse are calculated and converged. These CRPs are then analyzed for the properties of quantized dynamical bottlenecks that control microcanonical-ensemble rate constants for the Cl + H2 reaction and its reverse. Analysis of the total and state-specific rate constants provides compelling evidence that quantized transition states exist. more...

A study was conducted to analyze bromine peroxide, mixed bromine and chlorine peroxides, and their isomers using wave functional and density functional theory techniques. The form and relative stability of the species were examined using optimized geometries, harmonic frequencies, relative energies and isodesmic heats of formation. Results indicated the effectiveness of the methods in determining bond lengths. more...

The classical trajectory method was used to examine the reaction probability and product-state energy distribution in the Eley-Rideal reaction of atomic chlorine with hydrogen atoms chemisorbed on a silicon surface. All reactive elements were found to occur on a subpicosecond time scale at a gas temperature of 1500 K and a surface temperature of 300 K. The events are due to the efficient energy flow from the gas atom to the adatom-surface bond. The reaction probability was found to increase with increasing gas temperature, but remains constant above 1000 K. more...