Browsing by Author "Zhou, JG"

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Insights into dynamics of the F+CD4 reaction via product pair correlation
(2003-09-08)
Zhou, JG
;
Lin, JJ
;
Shiu, WC
;
Liu, KP
;
應用化學系
To unravel the "extra-atom" complexity of the title reaction, we exploit an experimental approach which, by taking advantage of the correlated information of coincident product pairs, allows us to peel off judiciously the intrinsic complications of a six-atom reaction, extracting the underlying backbone of three-atom dynamics. Examining the collisional energy dependencies of the pair-correlated attributes for a given state(s) of CD3 products from the title reaction, several of major observations can qualitatively be understood, whereas others await further theoretical investigations. An intriguing possibility for the existence of reactive resonances in this six-atom reaction is surmised. (C) 2003 American Institute of Physics.
Observation of a reactive resonance in the integral cross section of a six-atom reaction: F+CHD3
(2004-07-08)
Zhou, JG
;
Lin, JJ
;
Liu, KP
;
應用化學系
;
Department of Applied Chemistry
The title reaction was investigated under crossed-beam conditions at collisional energies ranging from about 0.4 to 7.5 kcal/mol. Product velocity distributions were measured by a time-sliced, velocity-map imaging technique to explicitly account for the density-to-flux transformation factors. Both the state-resolved, pair-correlated excitation functions and vibrational branching ratios are presented for the two isotopic product channels. An intriguing resonance tunneling mechanism occurring near the reaction threshold for the HF+CD3 product channel is surmized, which echoes the reactive resonances found previously for the F+HD-->HF+D reaction and more recently for the F+CH4 reaction. (C) 2004 American Institute of Physics.
On the Cl*(P-2(1/2)) reactivity and the effect of bend excitation in the Cl+CH4/CD4 reactions
(2004-09-30)
Zhou, JG
;
Lin, JJ
;
Zhang, BL
;
Liu, KP
;
應用化學系
The reaction of atomic chlorine with methane was studied in crossed-beam experiments at a collisional energy of E-c approximate to 4.7 kcal/mol. Using a time-sliced product imaging technique, several outstanding issues about this reaction were addressed in this work. It was found that the reactivity of the spin-orbit excited Cl*(P-2(1/2)) atom toward methane is negligibly small, in agreement with the assertion of recent studies. The excitation of methane bending/torsional modes exhibits only modest enhancement in reactivity, in contrast to the previous experiments. The product angular distributions are mainly backscattered for Cl + CD4, and sideways scattered for Cl + CH4. The shapes of the distributions from the ground state and the bend-excited methane are remarkably similar.
Rotationally selected product pair correlation in F+CD4 -> DF(nu('))+CD3(nu=0,N)
(2004-04-01)
Zhou, JG
;
Shiu, WC
;
Lin, JJ
;
Liu, KP
;
應用化學系
The title reaction was studied in a crossed-beam experiment by imaging of state-selected products. The rotational state selection of the CD3 products was achieved using (2+1) resonance-enhanced multiphoton ionization. The coincident information on the DF coproducts was revealed in a state-resolved manner from time-sliced velocity map images. Significant dependences of both the correlated differential cross sections and the DF vibrational branching ratios on the "tagged" CD3 rotation states were found. The dynamical implications of one of the major findings are discussed. (C) 2004 American Institute of Physics.