Motivated by the need to improve the understanding of radical-molecule reactivity, the rate constants for the reactions of the SD radical with an interhalogen series (Br2, BrCl, Cl2, and F2) were measured as a function of temperature with a discharge-flow apparatus. The SD radical was monitored by a laser-induced fluorescence technique. The reactions were found to proceed by halogen atom abstraction with the following bimolecular rate constants (95% confidence level, in units of cm3 molecule-1 s-1): SD + Br2 --> BrSD + Br, k1 = (6.0 +/- 1.5) x 10(-11) exp[(160 +/- 100)/T] for 273 K < T < 373 K; SD + BrCl --> products, k2 = (2.3 +/- 0.3) x 10(-11) exp[(350 +/- 80)/T] for 298 K < T < 373 K; SD + BrCl --> ClSD + Br, k2b = (2.3 +/- 2) x 10(-11) exp[(100 +/- 200)/T] for 298 K < T < 373 K; SD + Cl2 --> ClSD + Cl, k3 = (1.7 +/- 0.4) x 10(-11) exp[(-690 +/- 90)/T] for 273 K < T < 373 K; SD + F2 --> FSD + F, k4 = (4.3 +/- 1.4) x 10(-11) exp[(-1390 +/- 100)/T] for 298 K < T < 373 K. We examine these results within the framework of a reactivity trend that correlates the room-temperature rate constants with the parameter (IP - EA), where IP and EA represent the ionization potential of the electron density donating reactant and the electron affinity of the electron density acceptor, respectively. It was found that the trend fails for these and other halogen atom abstraction reactions unless a correction for the effects of polarizability is included.
Excitation of OH- and SH-Band Systems in Fluorescence
作者:P. J. DYNE、D. W. G. STYLE
DOI:10.1038/167899a0
日期:1951.6
Dawsey, Urey and Rice1 claimed to have excited the OH-band 3064 A. in fluorescence in hydrogenperoxide vapour, the processes involved being: H2O2 + hν1 → HO + OH* OH* → OH + hν2. In these experiments, light from a zinc spark was passed through an acetone filter, which removed light of wave-lengths shorter than λ 2025, down a quartz tube containing hydrogenperoxide vapour and thence to the slit of
Two-photon resonance enhanced MPI-PES above the lowest ionization threshold. Observation of the [a1Δ]5pπ 2Φ state of the SH (SD) radical
作者:J.B. Milan、W.J. Buma、C.A. de Lange、C.M. Western、M.N.R. Ashfold
DOI:10.1016/0009-2614(95)00488-p
日期:1995.6
A (2 + 1) resonance enhanced multiphoton ionization photoelectron spectroscopy (REMPI-PES) study of the hitherto unobserved Rydberg state of the SH (SD) radical is reported. Despite the fact that this state has an excitation energy which exceeds the lowest ionization energy, ionization is observed to occur preferentially by the absorption of a third photon after the two-photon excitation step, rather
Rotational state dependence of transient linewidths in the CO2 0001 vibrational level due to translational energy recoil from hot H and D atom collisions
作者:John F. Hershberger、James Z. Chou、George W. Flynn、Ralph E. Weston
DOI:10.1016/0009-2614(88)80347-6
日期:1988.8
The nascent transientlinewidths of the CO20001, J→0002, J−1 transitions were measured immediately following collisions with hotH and Datoms of 2.30 and 2.16 eV energy, respectively. All lineshapes were well fitted by Gaussian profiles, but were significantly broader than the room-temperature Doppler profiles. Datomcollisions resulted in broader linewidths than Hatomcollisions. The observed
Isotope effects in reactions of trifluoromethyl radicals with hydrogen chloride and hydrogen sulphide
作者:N. L. Arthur、Peter Gray
DOI:10.1039/tf9696500434
日期:——
Rate constants, Arrhenius parameters and primary kinetic isotope effects have been measured for the reactions of trifluoromethyl radicals with H2S, D2S, HCl and DCl: [graphic omitted] Quotients of A-factors do not differ significantly from unity, but values for (ED–EH) are significantly less than the respective zero-point-energy differences ΔE0 of 1.1 kcal mole–1. The reactivity of CF3 radicals towards the two substances is markedly less than that of CH3 radicals; the differences reside in the higher activation energies and may be attributed to the polar character of CF3.
Two-photon laser-induced fluorescence studies of HS radicals, DS radicals, and I atoms
作者:J.J. Tiee、M.J. Ferris、G.W. Loge、F.B. Wampler
DOI:10.1016/0009-2614(83)80723-4
日期:1983.4
A two-photon laser-induced excitation and fluorescence technique has been used to study the A 2Σ+-X 2Π transition of HS and DS radicals and various high-lying 4Po, 2Do, and 4Do states of the I atom. The two-photon excitation cross sections and detection sensitivity are discussed.
双光子激光诱导激发和荧光技术已用于研究阿2 Σ + -X 2 HS和DS自由基和各种高地势的Π过渡4 P ø,2 d ø,和4 d Ò的状态我原子。讨论了双光子激发截面和检测灵敏度。