摘要:

AbstractThe temperature dependence of the vibration–vibration energy transfer between thev3mode of N2O and the first vibrational level of CO was determined over a range of 780 to 1400°K using a shock tube. Several mixtures of CO‐N2O were tested, diluted in 95% Ar. The Landau–Teller plot of the vibration–vibration relaxation times has a least squares line of\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log}_{{\rm 10}} p\tau _{{\rm VV}} = 2.69T^{ - 1/3} - 1.70 $$\end{document}where pτvv is in atm ˙μsec andTin °K. The measured kinetic reaction was determined to be\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm N}_{\rm 2} {\rm O(001) + CO(O)} \to {\rm N}_{\rm 2} {\rm O}(000) + {\rm CO(1) + 81cm}^{{\rm - 1}} $$\end{document}The transfer probabilities for this process were found to vary directly with

ISSN:0538-8066    

DOI:10.1002/kin.550070102

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe gas‐phase photolysis of perfluoroacetone in the presence of ethane has been shown to result in the production of significant amounts of 1, 1‐bis(trifluoromethyl)propanol‐1, (CF3)2(C2H5)COH, and 1, 1, 4, 4‐tetrakis(trifluoromethyl)butane‐1, 4‐diol, (CF3)2C(OH)‐CH2CH2C(OH)(CF3)2. A mechanism is presented which accounts for the relative rates of formation of these products at roo

ISSN:0538-8066    

DOI:10.1002/kin.550070103

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe high‐temperature oxidation of formaldehyde in the presence of carbon monoxide was investigated to determine the rate constant of the reaction HO2+ CO  CO2+ OH (10). In the temperature range of 878–952°K from the initial parts of the kinetic curves of the HO2radicals and CO2accumulation at small extents of the reaction, when the quantity of the reacted formaldehyde does not exceed 10%, it was determined that the rate constantk10is\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{10} = (1.7 \pm 0.5) \times 10^{ - 10} \exp [ - (23,000 \pm 3000/RT)]\,{\rm cm}^{\rm 3} /{\rm molec}{\rm.sec} $$\end{document}A computer program was used to solve the system of differential equations which correspond to the high‐temperature oxidation of formaldehyde in the presence of carbon monoxide. The computation confirmed the experimental results. Also discussed are existing experimental data related to the reaction of HO

ISSN:0538-8066    

DOI:10.1002/kin.550070104

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe present study reports the measurement of the V–V energy transfer rates for the CO*COS system in the temperature range of 195 to 370°K. The measured rates exhibit a slight inverse temperature dependence. The experimental results are compared to prediction based on a model of long‐range dipole–dipole interactions between colliding molecules. The effect of single quantum rotational transitions is compared to that of multiquantum rotational tra

ISSN:0538-8066    

DOI:10.1002/kin.550070105

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractModified nuclear recoil techniques have been used to obtain accurate relative bimolecular rate coefficients for thermally induced hydrogen abstraction reactions by atomic fluorine. New results are reported for 12 hydrocarbons and partially fluorinated hydrocarbons studied at 303°K

ISSN:0538-8066    

DOI:10.1002/kin.550070106

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe mechanism of the electronically excited sulfur‐dioxide sensitized isomerization ofcis‐2‐butene has been studied through the measurement of the initial quantum yields oftrans‐2‐butene formation in 3130‐A irradiated gaseous binary mixtures of SO2andcis‐2‐butene and ternary mixtures of SO2,cis‐2‐butene, and CO2. The kinetic treatment of the present data from the SO2C4H8mixtures and those of recent similar studies of Penzhorn and Güsten [3] and Cox [4]are all consistent with the involvement of only the long‐lived fluorescent1B1and phosphorescent3B1states of SO2in the isomerization mechanism. The data give (k2a+k2b)=0.21±0.04; SO2(1B1) + SO2→ SO2(3B1) + SO2(2a); SO2(1B1) + SO2→ (2SO2) (2b). The analogous intersystem crossing ratio for the SO2(1B1)‐cis‐2‐butene quenching collisions is the largest observed among the many quencher molecules studied; the value lies in the range of 0.85 to 0.37, with the extremes representing different choices of alternative data and possible mechanisms. From the present data the ratio of the SO2(3B1) quenching rate constant with SO2to that withcis‐2‐butene as quencher is estimated to be (2.7±1.2) × 10−3, in good agreement with our directly measured ratio from lifetime studies (2.91±0.23) × 10−3[30−32], and the value found in isomerization studies by Cox (2.40±0.09) × 10−3[4]. The simple two‐excited state mechanism, which is seemingly applicable to the relatively low‐pressure binary SO2‐butene mixture results, is not adequate to explain the data obtained in experiments with large quantities of added CO2gas. Here an “excess” quantum yield of isomerization is observed. Several alternative mechanisms can be used to rationalize these results, but all alternatives must incorporate some other excited SO2species (X) as well as SO2(3B1) and SO2(1B1). The kinetics suggest that the ill‐defined state is unreactive toward the olefin and decays nonradiatively to SO2largely in experiments at the lower pressures, X → SO2(11); it may generate SO2(3B1) in a collisionally induced process at high added inert gas (CO2) pressures, X + CO2→ SO2(3B1) + CO2(10a)

ISSN:0538-8066    

DOI:10.1002/kin.550070107

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA kinetic investigation of electronically excited arsenic atoms in the low‐lying states, As(4p32DJ) and As(4p32PJ), ca. 1.33 and 2.28 eV, respectively, above the 44S3/2ground state, has been carried out by atomic absorption spectroscopy. Atoms in these optically metastable states were generated by the pulsed irradiation of suitable arsenic compounds (AsMe3for2Dand AsCl3for2P) in different spectral regions and monitored photoelectrically by time‐resolved attenuation of atomic resonance radiation. Rate constants for the deactivation of these two states are reported for a range of collision partners. The data are compared with those of the analogous states of lighter atoms in group V, namely,P(32DJ, 32PJ) andN(22DJ, 22PJ), and discussed in terms of spin and orbital symmetry considerati

ISSN:0538-8066    

DOI:10.1002/kin.550070108

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractElectronically excited tin atoms Sn(51D2), 1.068 eV above the 53P0ground state, have been generated by the pulsed irradiation of tin tetramethyl and monitored photoelectrically in absorption by time‐resolved attenuation of atomic resonance radiation at λ=285.06 nm [Sn((5d3F20) ← (5p21D2))]. Deactivation rate constants are reported for the quenching of Sn(51D2) with a range of collision partners and the resulting data are compared with those for analogous states within group IV, namely, C(21D2) and Pb(61D2). The data are discussed in terms of correlations based on both the weak and strong spin orbit coupling approximat

ISSN:0538-8066    

DOI:10.1002/kin.550070109

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe activation energy parameters for the reaction of PdX 4 2−(X=Cl−, Br−) in aqueous halide acid solution with thiourea (tu) and selenourea (seu) have been determined. High rates of reaction parallel low enthalpies and appreciable negative entropy of activation. The rate law in each case simplifies tokobs=k[L] where L=tu or seu, and only ligand‐dependent rate constants are observed at 25°C. The ligand‐dependent rate constants for the first identifiable step in the PdCl 4 2−+ X system is (9.1±0.1) × 103M−1sec−1and (4.5±0.1) × 104M−1sec−1for X=tu and seu, respectively, while for the PdBr 4 2−+ X system it is (2.0±0.1) × 104M−1sec−1and (9.0±0.1

ISSN:0538-8066    

DOI:10.1002/kin.550070110

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe photochemistry of azoisopropane is reinvestigated at 366 nm over an extended pressure range by usingn‐butane as an added bath gas, and over a range of temperature from 277° to 180°C. The Stern‐Volmer type plot of the N2product quantum yield is interpreted in terms of the decomposition of the vibrationally excited upper singlet and triplet states, with the onset of the dissociation of the vibrationally equilibrated triplet state as the temperature is increased. The energy barrier for the dissociation of the vibrationally equilibrated first triplet state is found to be 8.8 kcal/mole. Triplet sensitization experiments with biacetyl correlate with our observations, and it is suggested that the proposed mechanism is generally applicable to the photodissociation of acyclic azoalkanes at 366 nm, based on a comparison of our data with those of Wu and Rice on hexafluoroazome

ISSN:0538-8066    

DOI:10.1002/kin.550070111

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY