- Kinetic study of the reaction of chlorine atoms with chloroform in the gas phase
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The kinetics of the gas-phase reactions of chlorine atoms with H-chloroform and D-chloroform was studied experimentally. The relative rate method was applied using Cl + CH3Br as the reference reaction. The rate constants for H-abstraction from
- Gola, Agnieszka A.,Sarzyński, Dariusz,Dry?, Andrzej,Jodkowski, Jerzy T.
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- Kinetic study of the reaction of chlorine atoms with chloromethane in the gas phase
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The kinetics of the gas phase reactions of chlorine atoms with chloromethane and D-chloromethane CD3Cl was studied experimentally. The relative rate method was applied using Cl + CH3Br as the reference reaction. The rate constants fo
- Sarzyński, Dariusz,Gola, Agnieszka A.,Dry?, Andrzej,Jodkowski, Jerzy T.
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- Differential cross section polarization moments: Location of the D-atom transfer in the transition-state region for the reactions CI+C2D6→DCI(v′= 0, J′=1)+C2D5 and CI+CD4→DCI(v′=0,J′=1)+CD3
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The photoloc technique can permit the measurement of not only the state-to-state differential cross section but also its complete product polarization dependence for all moments of orientation and alignment with K≤2. We have realized this possibility for the reaction Cl+C2D6→DCl(v′=0,J′ =1)+C2D5 at a collision energy of 0.25 eV, for which we have measured the differential cross section, 1lσ(dσ00/dΩr), and the four polarization-dependent moments of the differential cross section, A1(1)stf, A0(2)stf, A1(2)stf and A2(2)stf, in the stationary target frame (STF), which are defined by Aq(k)stf=(dσkq stf/dΩr)/(dσ00/dΩ r). For the Cl+CD4→DCl(v′=0,J′=1)+CD3 reaction at a collision energy of 0.28 eV we have also determined 1/σ(dσ00/dΩr) and A0(2)stf. The laboratory speed distributions of the DCl(v′=0,J′=1) products are measured using 2+1 resonance-enhanced multiphoton ionization (REMPI) and the core-extraction technique. The polarization-dependent differential cross sections are determined from the dependence of the core-extracted profiles on the photolysis and probe polarizations. Recent studies have shown that the Cl+CD4 and Cl+C2D6 both show scattering behavior described by the line-of-centers model and both yield rotationally cold DCl products with little energy in the alkyl fragments. Despite these similarities, we measure DCl(v′=0,J′=1) product polarizations that differ greatly for these two reactions. For the Cl+CD4 reaction, we find that JDCl is maximally aligned perpendicular to an axis close to the product scattering direction, uDCl. For the Cl+C2D6 reaction, we find that JDCl is half-maximally aligned perpendicular to the line-of-centers direction. We interpret these results in terms of the location of the D-atom transfer along the reaction coordinate, positing that the D-atom transfer for the Cl+CD4 reaction occurs late in the reactive process and the D-atom transfer for the Cl+C2D6 reaction occurs earlier near the distance of closest approach. We interpret the difference in the locations of the D-atom transfer to be the cause of the large differences in the Arrhenius pre-exponential factors of the C1+CD4 and Cl+C2D6 reactions.
- Rakitzis, T. Peter,Kandel, S. Alex,Lev-On, Topaz,Zare, Richard N.
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- H/D isotope effects on formation and photodissociation of HKrCl in solid Kr
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The H/D isotope effects on formation and photodissociation of HKrCl in solid Kr were investigated. The formation kinetics of HKrCl and DKrCl reveals the isotope effect on thermally activated mobility of atomic hydrogen. Thus, the difference between the H and D mobilities allowed to show that a reaction of D atoms with HKrCl was taking place. Thus, the HKrCl and DKrCl photodecomposition rates were compared.
- Khriachtchev, Leonid
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- Infrared spectra and theoretical calculations of HCl complexed with NO
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The vibrational spectra of NO:HCl trapped in argon matrix have been reinvestigated. In the high frequency region, two stretching modes of N-O and H-Cl have been observed in agreement with a recent paper [Chem. Phys. 185 (1994) 365]. In the low frequency region, two bands (N-H stretch and out of plane bend) have been identified. From a theoretical study, it has been shown that the four experimental frequencies of the complex are well reproduced only for a bent structure in which H-bonding takes place between the nitrogen atom of NO and the hydrogen atom of HCl. The calculated frequency shifts of the N-O and H-Cl stretching modes upon complexation agree well with the experimental values.
- Krim,Alikhani
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- Infrared Spectroscopic and Electronic Structure Investigations of Beryllium Halide Molecules, Cations, and Anions in Noble Gas Matrices
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Laser-ablated Be atoms, cations, and electrons were reacted with F2, ClF, Cl2, NF3, CCl4, CF2Cl2, HCl, DCl, and SiCl4 diluted in noble gases. The major products were the dihalides BeF2, BeClF, BeCl2, and the hydride chloride HBeCl, whose identities were confirmed by comparison with previous evaporative work, deuterium substitution, and vibrational frequency calculations. The matrix-isolated fundamental frequency of the BeF molecule is higher, and the frequency of BeCl is lower, than that determined for the gas-phase molecules. The BeF+ and BeCl+ cations formed strong dipole-induced dipole complexes in solid Ne, Ar, Kr, and Xe with stepwise increase in computed noble gas dissociation energies. Going down the family NgBeF+ and NgBeCl+ series (Ng = Ne, Ar, Kr, Xe) the Mulliken charges q(Be) decrease, while q(Ng) increases, and the dipole moments decrease, which suggests covalent bonding in the xenon species. We find that the largest intramatrix shift is Ne to Ar which follows the largest factor increase for the Ng atomic polarizabilities. Extra electrons produce Cl-, which reacts with HCl to form the stable HCl2- anion and possibly with BeCl2 to give BeCl3-. A weak band observed in neon experiments with F2 is probably due to BeF3-.
- Yu, Wenjie,Andrews, Lester,Wang, Xuefeng
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- Kinetics of the Cl-H2 system. II. Abstraction vs exchange in D+HCl
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The gas phase reaction of D with HCl was studied at room temperature by the method of flash photolysis, with resonance fluorescence detection of D, H, and Cl atoms.The D and Cl atoms were observed to decay exponentially, whereas no H atom signal the excha
- Miller, John C.,Gordon, Robert J.
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- Infrared Spectra of the HAnX and H2AnX2 Molecules (An=Th and U, X=Cl and Br) in Argon Matrices Supported by Electronic Structure Calculations
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Uranium and thorium hydrides are known as functional groups for ligand stabilized complexes and as isolated molecules under matrix isolation conditions. Here, the new molecular products of the reactions of laser-ablated U and Th atoms with HCl and with HBr, namely HUCl, HUBr and HThCl, HThBr, based on their mid and far infrared spectra in solid argon, are reported. The assignment of these species is based on the close agreement between observed and calculated vibrational frequencies. The H?U and U?35Cl stretching modes of HUCl were observed at 1404.6 and 323.8 cm?1, respectively. Using DCl instead to form DUCl gives absorption bands at 1003.1 and 314.7 cm?1. The corresponding bands of HThCl are 1483.8 (H?Th) and 1058.0 (D?Th), as well as 340.3 and 335.8 cm?1 (Th?35Cl), respectively. HUBr is observed at 1410.6 cm?1 and the BP86 computed shift from HUCl is 6.2 cm?1 in excellent agreement. The U?H stretching frequency increases from 1383.1 (HUF), 1404.6 (HUCl), 1410.6 (HUBr) to 1423.6 cm?1 (UH) as less electronic charge is removed from the U?H bond by the less electronegative substituent. These U?H stretching frequencies follow the Mayer bond orders calculated for the three HUX molecules. A similar trend is found for the Th counterparts. Additional absorptions are assigned to the H2AnX2 molecules (An=U, Th, X=Cl, Br) formed by the exothermic reaction of a second HX molecule with the above primary products.
- Li, Lin,Stüker, Tony,Andrews, Lester,Beckers, Helmut,Riedel, Sebastian
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- Kinetics of the Cl-H2 system. III. The deuterium isotope effect in Cl + H2
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The rate constant for the reaction Cl+D2 was measured over the temperature range 200-500 K, using the flash photolysis-resonance fluorescence technique.These data, together with previous measurements for Cl+H2, are compared with the isotope effect measured by Persky and Klein in a static bulb.Over the range 295-500 K, our data are in excellent agreement with their results.At lower temperatures, the Cl+D2 rate constant displays an anomalous non-Arrhenius curvature.A mechanism involving the reaction of Cl atoms with vibrationally excited D2 is proposed to explain this effect.
- Miller, John C.,Gordon, Robert J.
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- Reactivity of auranofin with selenols and thiols - Implications for the anticancer activity of gold(I) compounds
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The enzyme thioredoxin reductase (TrxR) is attracting much interest as a potential target for cancer therapy. The presence of a selenium atom in the catalytic site makes it sensitive to inhibition by electrophilic molecules, including the AuI complex auranofin [2,3,4,6-tetra-O-acetyl-1-thio- β-D-glucopyranosato-S-(triethylphosphane)gold]. The reactions between auranofin and models of thiol and selenol nucleophiles present in TrxR (PhSH and PhSeH) have been investigated in chloroform and methanol by means of 1H, 31P, and 77Se NMR spectroscopy. In chloroform, auranofin undergoes ligand substitution of the tetraacetylthioglucose moiety by a PhS or PhSe group. The reaction is reversible in both cases, but it is characterized by widely different equilibrium constants (ca. 1 for S and at least 103 for Se). In polar solvents, such as methanol, the reaction is more complex, and the phosphane moiety also undergoes ligand exchange. Some features have been clarified through the investigation of Et3PAuCl. The elementary processes involved have been characterized by DFT calculations. Copyright
- Di Sarra, Francesca,Fresch, Barbara,Bini, Riccardo,Saielli, Giacomo,Bagno, Alessandro
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p. 2718 - 2727
(2013/07/11)
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- Kinetic study of the reaction of chlorine atoms with dichloromethane and D-dichloromethane in the gas phase
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The kinetics of the gas-phase reactions of chlorine atoms with dichloromethane (CH2Cl2) and D-dichloromethane (CD 2Cl2) was studied using the relative rate method with Cl + CH3Br as the reference reaction. The rate constants for H-abstraction from CH2Cl2 (kH) and D-abstraction from CD2Cl2 (kD) were measured in the temperature range of 298-527 K and at a total pressure of 100 Torr using N2 as a diluent. The temperature dependencies of the rate constants (with the 2σ error limits) are described by the expressions: kH = (8.69 ± 0.82) × 10-12 × exp(-955 ± 20/T) and kD = (6.98 ± 0.91) × 10-12 × exp(-1285 ± 25/T) cm3 molecule-1 s-1. The kinetic isotope effect, described by the ratio kH/kD, was found of 3.8 ± 0.2 at room temperature.
- Sarzyński, Dariusz,Gola, Agnieszka A.,Brudnik, Katarzyna,Jodkowski, Jerzy T.
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p. 220 - 225
(2011/11/28)
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- Neon matrix-isolation infrared spectrum of HOOCl measured upon the VUV-light irradiation of an HCl/O2 mixture
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Vacuum ultraviolet (VUV) photolysis of an HCl/O2 mixture has been carried out to identify HOOCl by the Ne matrix-isolation infrared spectroscopy with the aid of quantum chemical calculations. Newly-observed IR bands at 823, 1363 and 3542 cm-1 are assigned to those of HOOCl on the basis of the isotope shifts with DOOCl and the CCSD(T)/aug-cc-pVDZ calculation. The observed dependence of band intensities on the time of VUV photolysis indicates that HOOCl and HOClO are the photoproducts formed in an early stage. In addition, HOOCl is found to decompose to form HCl in the UV photolysis (λ ≥ 365 nm), which consists with the S1-S0 energy separation estimated by the TDDFT method.
- Yoshinobu, Takeo,Akai, Nobuyuki,Kawai, Akio,Shibuya, Kazuhiko
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- Matrix isolation investigation of the photochemical reaction of activator-substituted benzenes with CrCl2O2
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The matrix isolation technique, combined with infrared spectroscopy and theoretical calculations, has been used to characterize the products of the photochemical reactions of aniline, anisole, and N,N-dimethylaniline with CrCl2O2. While initial twin jet deposition of the reagents did not lead to product formation, new bands were noted following irradiation with light of λ > 300 nm. In the reactions of CrCl2O2 and aniline, irradiation led to HCl formation, very likely accompanied by CrClO2(H)NC6H5 formation, and a mixture of isomers of CrCl2O-aminocyclohexa-2,4-dienone via oxygen atom transfer. CrCl2O2 and aniline were also codeposited as cryogenic thin films, producing new bands. Irradiation of these films led to further growth of these bands. The same products were identified in the thin film studies as were observed in the argon matrix experiments. The irradiation of the matrices containing CrCl2O2 and anisole and N,N-dimethylaniline were shown to lead to oxygen atom transfer, forming complexes between the corresponding cyclic ketone derivatives and CrCl2O. The identification of the complexes were supported by density functional calculations at the B3LYP/6-311G++(d,2p) level and isotopic labeling (in the case of aniline).
- Hoops, Michael D.,Ault, Bruce S.
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p. 277 - 290
(2009/02/06)
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- The tetracyanoboronic acids H[B(CN)4]·n H 2O9 n = 0, 1, 2
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Treatment of an aqueous solution of Na[B(CN)4] with an acidic cation exchange resin leads to a solution of the strong tetracyanoboronic acid. Evaporation of the solution at room temperature yields colourless single crystals of [H5O2][B(CN)4] (P4n2, a = 9.5830(2) A, c = 14.25440(3) A, Z = 1). Further drying of [H 5O2][B(CN)4] (mp. 115 °C) in vacuum at 50 °C gives polycrystalline [H3O][B(CN)4] (P6 3mc, a = 8.704(1) A, c = 6.152(1) A, Z = 2), which is thermally stable up to 145 °C The anhydrous polycrystalline acid H[B(CN)4] is formed quantitatively by reacting Me 3SiNCB(CN)3 with gaseous HCl. This acid starts to decompose at 190 °C with loss of HCN. All three acids were further characterized by vibrational spectroscopy, and elemental analysis.
- Kueppers, Torsten,Bernhardt, Eduard,Lehmann, Christian W.,Willner, Helge
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p. 1666 - 1672
(2008/10/09)
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- A velocity map imaging study of the one and two photon dissociations of state-selected D Cl+ cations
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D Cl+ (X Π 32 2, v+″ =0) cations have been prepared by 2+1 resonance enhanced multiphoton ionization, and their subsequent fragmentation following excitation at numerous wavelengths in the range of 240-350 nm studied by velocity map imaging of the resulting Cl+ products. This range of excitation wavelengths allows selective population of A +2 state levels with all vibrational (v+′) quantum numbers in the range 0≤ v+′ ≤15. Image analysis yields wavelength dependent branching ratios and recoil anisotropies of the various D+ Cl+ (PJ3, D1, and S1)product channels. Levels with 10≤ v+′ ≤15 have sufficient e nergy to predissociate, forming D+ Cl+ (PJ3) products with perpendicularrecoil anisotropies-consistent with the A +2 X Π2 parent excitation and subsequent fragmentation on a time scale that is fast compared with the parent rotational period. Branching into the various spin-orbit stat es of the Cl+ (PJ3) product is found to depend sensitively upon v+′ and, in the case of the v+′ =13 level, to vary with the precise choice of excitation wavelength within the A +2 X Π2 (13,0) band. Such variations have been rationalized qualitatively in terms of the differing contributions made to the overall predissociation rate of D Cl+ (A, v+′) molecules by coupling to repulsive states of Π4, -4, and -2 symmetries, all of which are calculated to cross the outer limb of theA +2 state potential at energies close to that of the v+′ =10 lev el. Cl+ (PJ3) fragments are detected weakly following excitation to A +2state levels with v+′ =0 or 1, Cl+ (D1) fragments dominate the io n yield when exciting via 2≤ v+′ ≤6 and via v+′ =9, while Cl+ (S1) fragments dominate the Cl+ images obtained when exciting via levels with v+′ =7 and 8. Analysis of wavelength resolved actionspectra for forming these Cl+ ions and of the resulting Cl+ ion images shows that (i) these ions all arise via two photon absorption processes, resonance enhanced at the one photon energy by the various A (v+′ A +2 X Π2 absorption step is saturated u nder the conditions required to observe significant two photon dissociation, and (iii) the final absorption step from the resonance enhancing A (v+′) level involves a parallel transition.
- Webb, Alexander D.,Nahler, N. Hendrik,Dixon, Richard N.,Ashfold, Michael N. R.
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- Matrix reactivity of AlF and AlCl in the presence of HCl and HBr: Generation and characterization of the new Al(III) hydrides HAlFCl, HAlFBr, and HAlClBr and the monomeric mixed Al(III) halides AlX2Y (X, Y = F, Cl, or Br)
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The spontaneous and photolytically induced reactions of AlF and AlCl in the presence of HCl and HBr in solid argon matrices were followed and the products identified and characterized by means of IR spectroscopy. Quantum mechanical calculations allow for a further evaluation of the properties of the reaction products. These are the adducts AlF·HCl, AlF·HBr, and AlCl·HBr, representing the products of spontaneous reactions, and the trivalent Al(III) hydrides HAlFCl, HAlFBr, and HAlClBr, which were formed upon photoactivation of these complexes. All three hydrides are planar molecules (Cs symmetry) with bond angles in agreement with the predictions of the VSEPR theory. In addition, the mixed halides AlFCl2, AlFBr2, and AlClBr2 were formed upon photolysis. The bisadducts AlF·(HCl)2 and AlF·(HBr)2 are likely to be the precursors to these species.
- Himmel, Hans-Joerg,Bahlo, Jan,Haussmann, Michael,Kurth, Fabian,Stoesser, Gregor,Schnoeckel, Hansgeorg
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p. 4952 - 4960
(2008/10/08)
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- Matrix isolation study of intermediates in the reaction of CrCl2O2 with CH3SH and (CH3)2S
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Initial and secondary intermediates in the reaction of CrCl2O2 with CH3SH and (CH3)2S have been characterized by matrix isolation infrared spectroscopy and density functional calculations. Twin jet codeposition of these reagents led to a series of infrared absorptions that are assigned to the 1:1 molecular complexes CH3SH·CrCl2O2 and (CH3)2S·CrCl2O2. The complexes were characterized by the shifts of Cr=O, Cr-Cl and S-H stretching modes. Irradiation of these matrices with light of λ > 300 nm led to complete destruction of the complexes, and for each system the growth of a number of new bands. For the CH3SH/CrCl2O2 system, these are assigned to the ClCr(O)2SCH3 species, as well as to HCl arising from destruction of the complex. Identification of these species was supported by deuterium labeling as well as by density functional calculations. Good agreement was observed between the experimental and computed frequencies. For the (CH3)2S/CrCl2O2 system, photolysis product bands are tentatively assigned to CH3Cl and ClCr(O)2SCH3.
- Anderson, Susan R.,Ault, Bruce S.
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p. 149 - 157
(2007/10/03)
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- A cryospectroscopic study of the oligomers of deuterium chloride in liquid argon, liquid krypton and in liquid nitrogen
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The infrared spectra of HCl and DCl dissolved in liquid argon (94-148 K) in liquid krypton (117-167 K) and in liquid nitrogen (94-148 K) with mole fractions varying between 0.5×10-4 and 2.5 × 10-3 are discussed. In all solutions, bands proving the existence of oligomeric species (DCl)x were observed. Analysis of the spectra shows that these bands must be assigned to dimeric, trimeric and tetrameric species.
- Herrebout,Van Gils,Van Der Veken
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p. 249 - 255
(2007/10/03)
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- Direct determination of the spin-orbit reactivity in CI(2P3/2, 2P1/2) + H2/D2/HD reactions
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Relative cross sections of the two spin orbit states in the Cl(2P)+H2 reeaction systems was presented. Large nonadiabatic reactivity was brought about by comparing the double differential cross sections of this reaction from the two
- Dong,Lee,Liu
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p. 1197 - 1204
(2007/10/03)
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- Isotope effects in the deactivation of O( 1 D) atoms by XCl and XF (X=H,D)
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The method of time-resolved laser magnetic resonance (LMR) was used to study the deactivation of O(1D) by HCl, DCl, HF, and DF at room temperature. For O(1D)+XF(X=H,D), the effect of deuteration on the rates of physical quenching and
- Chichinin
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p. 425 - 432
(2008/10/08)
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- The ultraviolet photodissociation of DCl:H/D isotope effects on the Cl((2)P) atom spin-orbit branching
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The photodissociation of jet-cooled DCl molecules subsequent to excitation in the long-wavelength tail of the first UV absorption band (A(1)Π(1) X(1)Σ(+)) has been investigated at five wavelengths in the range 200-220 nm. Ground state Cl((2)P(3/2)) and spin-orbit excited Cl(*)((2)P(1/2)) photofragments were monitored using (2+1) resonance enhanced multiphoton ionization in a time-of-flight mass spectrometer. The product branching fractions are reported and compared with previous experimental results and high-level quantum mechanical calculations for HCl and DCl. A significant H/D isotope effect in the branching fractions is found at all the studied wavelengths, in quantitative agreement with recent theoretical predictions.
- Ascenzi, D.,Regan, P. M.,Orr-Ewing, A. J.
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p. 477 - 484
(2008/10/08)
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- Infrared frequency-modulation measurements of absolute rate coefficients for Cl+HD→HCl(DCl)+D(H) between 295 and 700 K
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Absolute rate coefficients and HCl branching fractions for the Cl+HD reaction have been measured. The rate coefficient for Cl+HD is fit well by k1=(1.28±0.18)×10-16 T1.67 e-(1646±60)/T cm3 moleculesu
- Taatjes, Craig A.
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- Thermal rate constants for the Cl+H2 and Cl+D2 reactions between 296 and 3000 K
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Rate constants for the Cl+H2 and D2 reactions have been measured at room temperature by the laser photolysis-resonance absorption (LP-RA) technique.Measurements were also performed at higher temperatures using two shock tube techniques; laser photolysis-shock tube (LP-ST) technique with Cl-atom atomic resonance absorption spectrometric (ARAS) detection, over the temperature range 699-1224 K; and higher temperature rates were obtained using both Cl-atom and H-atom ARAS techniques with the thermal decomposition of COCl2 as the Cl-atom source.The combined experimental results are expressed in three parameter form as kH2(+/-15percent) = 4.78x10-16 T1.58 exp(-1610 K/T) and kD2(+/-20percent) = 9.71x10-17T1.75 exp(-2092 K/T) cm3 molecule-1 s-1 for the 296-3000 K range.The present results are compared to earlier direct studies which encompass the temperature ranges 199-1283 (H2) and 255-500 K (D2).These data including the present are then used to evaluate the rate behavior for each reaction over the entire experimental temperature range.In these evaluations the present data above 1300 K was given two times more weight than the earlier determinations.The evaluated rate constants are: kH2(+/-14percent) = 2.52*10-11 exp(-2214 K/T) (199TH2(+/-17percent) = 1.57*10-16 T1.72 exp(-1544 K/T) (354T2939 K), and kD2(+/-5percent) = 2.77*10-16 T1.62 exp(-2162 K/T) (255T3020 K), in molecular units.The ratio then gives the experimental kinetic isotope effect, KIE (kH2/kD2.Using 11 previous models for the potential energy surface (PES), conventional transition state theoretical (CTST) calculations, with Wigner or Eckart tunneling correction, are compared to experiment.At this level of theory, the Eckart method agrees better with experiment; however, none of the previous PES's reproduce the experimental results.The saddle point properties were then systematically varied resulting in an excellent model that explains all of the direct data.The theoretical results can be expressed to within +/-2percent as kH2th = 4.59*10-16 T1.588 exp(-1682 K/T) (200T2950 K) and kD2th = 9.20x10-16 T1.459 exp(-2274 K/T) cm3 molecule-1 s-1 (255T3050 K).The KIE predictions are also compared to experiment.The derived PES is compared to a new ab initio calculation, and the differences are discussed.Suggestions are noted for reconciling the discrepancies in terms of better dynamics models.
- Kumaran, S. S.,Lim, K. P.,Michael, J. V.
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p. 9487 - 9498
(2007/10/02)
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- Chemical dynamics of the reaction between chlorine atoms and deuterated cyclohexane
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The dynamics of the reaction Cl + cyclohexane-d12 (c-C6D12) → DCl + C6D11 have been investigated by using time-resolved diode laser absorption spectroscopy to probe the reaction product DCl. The chlorine atoms have been generated by the UV photolysis of S2C12 and NOCl. Nascent DCl produced in the reaction is rotationally cold (below room temperature) and translationally hot. As the collision energy increases, the DCl product translational energy increases dramatically, the rotational energy increases slightly, and the vibrational energy remains essentially the same. Most of the initial translational collision energy appears as translational energy of the reaction products, and this observation can be simply explained as being a result of the heavy-light-heavy atom reaction kinematics. An extremely simple spectator model, where C6D11 is the spectator, fits this experimental result very well. The cold DCl rotational state distribution may be an indication that Cl atoms abstract D atoms with a collinear C-D-Cl recoil geometry. Quasi-classical trajectory calculations using an empirical three-body model LEPS surface (C6D11 is considered as a structureless particle) successfully predict a number of the experimental results.
- Park, Jeunghee,Lee, Yongsik,Hershberger, John F.,Hosseolopp, Jeanne M.,Flynn, George W.
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- Very Low Pressure Reactor Chemiluminescence Studies on N Atom Reactions with CHCl3 and CDCl3
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Ground-state (N(S4)) nitrogen reactions with chloroform-h and chloroform-d were studied by using the VLPR technique at room temperature.Relative N atom concentrations were monitored via mass spectrometry, and their absolute values were determined by the chemical titration reaction with nitric oxide.It was possible to obtain a more accurate rate constant for the bimolecular reaction: N + NO ---> N2 + O, kNO = (2.4 +/- 0.2) x 10-11 cm3 molecule-1 s-1 at298 K.N atom decay in the presence of CHCl3 and CDCl3 was found to have an apparent induction period and to have a large isotope effect.Chemiluminescence signals emitted from the reactor in the range 300-600 nm were also observed, and identified as coming from the excited CN radical.The detailed study of reaction products, intermediates, N atom decay kinetics, and chemiluminescence signals are interpreted by slow reaction of Cl atoms with CHCl3 followed by fast branching chain reactions of N atoms with the intermediate radicals.A successful numerical simulation of the experimental results supports the suggested chain branching mechanism.The following rate constants were estimated from the experimental results: k1(N + CHCl3 ---> NCl + CHCl2), 1.00 x 10-16, k2(N + NCl ---> N + Cl), 2.57 x 10-11, k3(Cl + CHCl3 ---> HCl + CCl3), 3.70 x 10-14, k3D(Cl + CDCl3 ---> DCl + CCl3),0.95 x 10-14, k4(N + CHCl2 ---> HCN + 2Cl), 1.98 x 10-11, k5(N + CCl3 ---> ClCN + 2Cl), 1.67 x 10-11, k6(N + ClCN ---> CCl + N2), 1.00 x 10-14, and k7(N + CCl ---> CN(B2Σu+) + Cl), 5.70 x 10-13, all in the units of cm3 molecule-1 s-1.
- Jeoung, Sae Chae,Choo, Kwang Yul,Benson, Sidney W.
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p. 7282 - 7290
(2007/10/02)
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- Kinetics and Product Vibrational Energy Disposal Dynamics in the Reaction of Chlorine Atoms with D2S
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The reaction of chlorine atoms with D2S, forming DCl and DS, has been investigated by using time-resolved infrared diode laser absorption spectroscopic probing of both the D35Cl and D37Cl product.The rate constant obtained by using t
- Hossenlopp, Jeanne M.,Hershberger, John F.,Flynn, George W.
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p. 1346 - 1351
(2007/10/02)
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- Kinetics and Thermochemistry of the Reaction C2D6 + Cl C2D5 + DCl. The Heat of Formation of the C2D5 and C2H5 Radicals
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The bimolecular rate constant for the title reaction has been measured with the very low pressure reactor technique (VLPR) at 295 K.The rate constant at room temperature (295 K) was found to be k1=(8.30+/-0.7)x1E-12 cm3/(molecule*s).
- Parmar, Sucha S.,Benson, Sidney W.
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- Thermodynamics of Hydrogen-Isotope-Exchange Reactions. 3. An Experimental Test of the Born-Oppenheimer Approximation
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This paper reports the results of an experimental electrochemical test of the Born-Oppenheimer approximation for the hydrogen-isotope-exchange reaction D2(g) + 2HCl(g) ->/- H2(g) + 2DCl(g).The reaction was investigated in electrochemical double cells of
- Postma, James M.,Silvester, Leonard F.,Rock, Peter A.
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p. 1308 - 1312
(2007/10/02)
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- Infrared Chemiluminescence and Laser-Induced Fluorescence Studies of Energy Disposal by Reactions of F and Cl Atoms with H2S (D2S), H2Se, H2O (D2O), and CH3OH
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The vibrational energy disposal to HF (DF), HCl (DCl), SH (SD), and CH3O and relative product formation rate constants were measured for the title reactions.The experiments were done in a fast-flow reactor with infrared emission and laser-induced fluorescence to observe nascent product state distributions for the diatomic hydride products.The CH3O vibrational and HF (DF) rotational distributions are partially relaxed, but the nascent distributions for these cases were estimated.Laser-induced fluorescence measurements showed that the SH, SD, and CH3O fragments received only 0.02-0.03 of the available energy.The v(HX)> values for group VI (group 16) hydrides, 0.45 (F + H2S), 0.44 (F + D2S), 0.48 (F + H2Se), 0.42 (F + D2O), 0.41 (Cl + H2Se), and 0.37 (Cl + D2S), are similar but distinctly smaller than for F and Cl atom reactions with group IV and VII (group 14 and 17) hydrides.The R(HX)> values, 0.18 (F + H2S), 0.19 (F + H2Se), and ca.0.14 (F + D2S), are typical for H-abstraction reactions with similar cross sections.The F + H2O/D2O systems were used to characterize the extent of secondary reactions in the fast-flow reactor.For high reagent concentrations and longer reaction times, S2 was observed in the F/Cl + H2S systems by LIF.
- Agrawalla, B. S.,Setser, D. W.
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p. 2450 - 2462
(2007/10/02)
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- Infrared Spectrum of Dichloroborane Produced by CO2 Laser Enhanced Reaction
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Infrared spectra of HBCl2 and DBCl2 produced by a TEA CO2 laser enhanced reaction of BCl3 and H2/D2 have been observed by an FT-IR spectrometer at a resolution of 0.12 cm-1.A detailed analysis has been carried out for the ν1 band of
- Lee, Kuk-Haeng,Takeo, Harutoshi,Kondo, Shigeo,Matsumura, Chi
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p. 1772 - 1777
(2007/10/02)
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- Multistep cyclometalation of solid trans-dichloro[3,3′-oxybis[((diphenylphosphino)methyl)-benzene]] platinum(II)
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A solid complex of a new trans-spanning bis(phosphine) ligand, trans-dichloro[3,3′-oxybis[((diphenylphosphino)methyl)benzene]] platinum(II), trans-PtCL2(PoP), I, undergoes thermolysis at ca. 250°C with evolution of 2 mol of HC1 to form a doubly cyclometalated complex, [3,3′-oxybis[((diphenylphosphino)methyl)benzen]ato(2-)-C 2,C2′,P,P′]platinum(II), Pt(PoP-2H), II. Deuterium labeling in different positions (Chart I) shows that during thermolysis, approximately one ortho hydrogen of the phosphino phenyl groups is replaced by a HA proton (Chart I). This rearrangement is interpreted by a sequence of cyclometalation steps (Figure 5), one of which leads to an intermediate four-membered metallacycle. The reacting solid was investigated by thermogravimetry (TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC), partly with on-line mass spectral monitoring of the gaseous reaction product, by heating X-ray powder diffraction, and by optical microscopy. The results indicate that a short-lived fluid phase is involved when the reaction is carried out under optimal conditions.
- Baltensperger, Urs,Günter, John R.,K?gi, Stephan,Kahr, Günter,Marty, Werner
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p. 571 - 578
(2008/10/08)
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- Infrared Chemiluminescence Studies of Cl + Hi, HBr, DBr, PH3, PD3, and GeH4: Vibrational Energy Disposal and Rate Constants
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The Cl + HI, HBr, DBr, GeH4, PH3, and PD3 reactions were studied at room temperature with infrared chemiluminescence from a flowing afterglow apparatus.The HCl and DCl vibrational energy distributions and the relative rate constants for Cl + PH3, GeH4 and HI were measured.Since the rate constant for the Cl + HI reaction is available in the literature, the relative measurements can be converted to absolute rate constants.The HCl distribution from Cl + HI was ν1:ν2:ν3:ν4 = 0.07:0.24:0.49:0.20, which is in good agreement with cold-wall, arrested-relaxation results.The vibrational energy distributions are ν1:ν2:ν3 = 0.79:0.19:0.02 for GeH4, ν1:ν2:ν3 = 0.54:0.43:0.03 for PH3, ν1:ν2:ν3:ν4 = ).20:0.48:0.22:0.10 for PD3, ν1:ν2 = 0.75:0.25 for HBr, and ν1:ν2:ν3: = 0.33:0.55:0.12 for DBr.The Cl + GeH4 and PH3 reactions are approximately two times faster than Cl + HI.Einstein coefficients for a range of vibrational-rotational levels of HCl, HF, DCl, and DF are presented in the Appendix.
- Wickramaaratchi, M. A.,Setser, D. W.
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- CHEMICAL REACTIONS OF H AND D ATOMS WITH NO2 AND CINO, A CROSSED MOLECULAR BEAM STUDY.
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The chemical reactions of H and D atoms with NO//2 and CINO have been studied at a collision energy E equals 0. 44 eV (42 kJ/mol) in a crossed molecular beam experiment. Velocity and angular distributions were measured and are used to construct the center of mass (CM) distributions. The earlier reported isotope effect of the angular distributions for H, D plus NO//2 is shown to be due to the different CM to LAB conversions. The CM angular distribution is nearly isotropic for H plus NO//2, but shows strong backward peaking for H plus CINO. The measured translational energy spectra are in agreement with recent fluorescence and chemiluminescence results. The reaction H plus NO//2 proceeds via a long lived intermediate complex, while H plus CINO is a direct reaction.
- Haberland,von Lucadou,Rohwer
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p. 507 - 513
(2007/10/02)
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