We study the H＋CH4/CD4-＋H2/HD＋CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the （2＋1） resonance enhanced multi-photon ionization ...We study the H＋CH4/CD4-＋H2/HD＋CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the （2＋1） resonance enhanced multi-photon ionization （REMPI） detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.展开更多
The vacuum ultraviolet photodissociation of OCS via the F 3^1ΠRydberg states was investigated in the range of 134-140 nm by means of the time-sliced velocity map ion imaging technique.The images of S(^1D2)products fr...The vacuum ultraviolet photodissociation of OCS via the F 3^1ΠRydberg states was investigated in the range of 134-140 nm by means of the time-sliced velocity map ion imaging technique.The images of S(^1D2)products from the CO(X^1Σ^+)+S(^1D2)dissociation channel were acquired at five photolysis wavelengths,corresponding to a series of symmetric stretching vibrational excitations in OCS(F 3^1Π,v1=0-4).The total translational energy distributions,vibrational populations and angular distributions of CO(X^1Σ^+,v)coproducts were derived.The analysis of experimental results suggests that the excited OCS molecules dissociate to CO(X^1Σ^+)and S(^1D2)products via non-adiabatic couplings between the upper F 3^1Πstates and the lower-lying states both in the C∞v and Cs symmetry.Furthermore,strong wavelength dependent behavior has been observed:the greatly distinct vibrational populations and angular distributions of CO(X^1Σ^+,v)products from the lower(v1=0-2)and higher(v1=3,4)vibrational states of the excited OCS(F 3^1Π,v1)demonstrate that very different mechanisms are involved in the dissociation processes.This study provides evidence for the possible contribution of vibronic coupling and the crucial role of vibronic coupling on the vacuum ultraviolet photodissociation dynamics.展开更多
基金supported by the National Natural Science Foundation of China(No.22125302,No.22173099,No.22288201,No.21873089,and No.21973037)the Guangdong Science and Technology Program(No.2019ZT08L455 and No.2019JC01X091)the Shenzhen Science and Technology Program(No.ZDSYS20200421111001787).
文摘We study the H＋CH4/CD4-＋H2/HD＋CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the （2＋1） resonance enhanced multi-photon ionization （REMPI） detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.
基金supported by the National Key R&D Program of China(No.2017YFF0104500)the National Natural Science Foundation of China(No.21473173,No.21590802,No.21673216,and No.21773213)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB17000000).
文摘The vacuum ultraviolet photodissociation of OCS via the F 3^1ΠRydberg states was investigated in the range of 134-140 nm by means of the time-sliced velocity map ion imaging technique.The images of S(^1D2)products from the CO(X^1Σ^+)+S(^1D2)dissociation channel were acquired at five photolysis wavelengths,corresponding to a series of symmetric stretching vibrational excitations in OCS(F 3^1Π,v1=0-4).The total translational energy distributions,vibrational populations and angular distributions of CO(X^1Σ^+,v)coproducts were derived.The analysis of experimental results suggests that the excited OCS molecules dissociate to CO(X^1Σ^+)and S(^1D2)products via non-adiabatic couplings between the upper F 3^1Πstates and the lower-lying states both in the C∞v and Cs symmetry.Furthermore,strong wavelength dependent behavior has been observed:the greatly distinct vibrational populations and angular distributions of CO(X^1Σ^+,v)products from the lower(v1=0-2)and higher(v1=3,4)vibrational states of the excited OCS(F 3^1Π,v1)demonstrate that very different mechanisms are involved in the dissociation processes.This study provides evidence for the possible contribution of vibronic coupling and the crucial role of vibronic coupling on the vacuum ultraviolet photodissociation dynamics.
