We have investigated the photodissociation of vinyl chloride (H2CCHCl) at 193 nm using the technique of photofragment translational spectroscopy. The experiments were performed at the Chemical Dynamics Beamline at the Advanced Light Source and used vacuum ultraviolet synchrotron radiation for product photoionization. We have observed five primary dissociation channels following an initial π*←π excitation. The majority of Cl atoms originate from an excited-state dissociation. The remaining dissociation channels are consistent with competition on the ground electronic state following internal conversion from the optically prepared state. These channels include atomic and molecular hydrogen elimination, HCl elimination, and a translationally slow Cl elimination channel. We have also identified and characterized two secondary decomposition channels: (1) the elimination of Cl from chlorovinyl radicals following the primary atomic hydrogen elimination channel, and (2) hydrogen atom elimination from vinyl radica...

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Primary and secondary processes in the 193 nm photodissociation of vinyl chloride

Superalkalies with low ionization potentials (IPs) can exhibit behaviors reminiscent of alkali atoms and hence be considered as potential building blocks for the assembly of novel nanostructured materials. A new series of binuclear superalkali cations M(2)Li(2k+1)(+) (M = F, O, N, C) has been studied using ab initio methods. The structural features of such cations are found to be related to the central atoms. In the preferred structures of F(2)Li(3)(+), O(2)Li(5)(+), and N(2)Li(7)(+), two central atoms are bridged by lithium atoms. While in the global minima of C(2)Li(9)(+), two central carbon atoms directly link each other and the C-C unit extends to the surface of the whole system. These M(2)Li(2k+1)(+) species exhibit very low vertical electron affinities of 2.74-4.61 eV at the OVGF/6-311+G(3df) level and hence should be classified as superalkali cations.

Ab Initio Investigation on a New Class of Binuclear Superalkali Cations M2Li2k+1+ (F2Li3+, O2Li5+, N2Li7+, and C2Li9+)

A new series of polynuclear superalkali cations YLi3+ (Y = CO3, SO3, SO4, O4, and O5) has been created when the central group is surrounded by alkali atoms. The structural characteristics and stabilities of these systems are provided on the basis of ab initio methods. In the lowest-energy structure of the CO3Li3+, SO3Li3+, and SO4Li3+ cations, the central Y (Y = CO3, SO3, and SO4) group features a slight distortion. The global minima of O4Li3+ and O5Li3+ are of the forms O2–(Li+)3O2– and O2–(Li+)3O3–, respectively, both of which contain two monovalent ion units. The structural integrity of the central Y group and the arrangement of the lithium ligands are two influencing factors on the vertical electron affinities (EAvert) for the YLi3+ species. The YLi3+ cation, with its lithium ligands being distributed evenly or far from each other, tends to exhibit a low EAvert value, whereas a greater extent of cleavage of the central Y group leads to a higher EAvert value and even makes some species lose their super...

Theoretical study on polynuclear superalkali cations with various functional groups as the central core.

Prompted by the stability of some lithium decorated star-like clusters and super-alkali systems, their hydrogen trapping potential is assessed at the M06/6-311+G(d,p) and the M052X/6-311+G(d) levels, respectively. The effect of an applied electric field is also analyzed. Most of these systems are found to have the potential to become effective hydrogen storage materials with high gravimetric weight percent owing to the charges on the Li centers. The presence of an external electric field improves the situation.

The hydrogen trapping potential of some Li-doped star-like clusters and super-alkali systems

The chemistry of the Fricke dosimeter induced by low and high linear energy transfer (LET) radiation has been modeled using the stochastic IRT method, incorporating simulated ion tracks. Comparison of the results for track segments with experimentally determined differential yields shows excellent agreement for energetic electrons, and for nonrelativistic ions, including 1H, 4He, 12C, and 20Ne. There is a significant effect of particle type and energy on the response of the Fricke dosimeter, which reflects the competition between intra-track reaction of the radiation-induced radicals, diffusion, and scavenging. This competition is modified by changes in the ion track structure. Monte Carlo track structure simulations show that the radial energy loss profiles are similar for ions with the same velocity/charge ratio and that ∼40% of the energy is initially deposited within a water diameter of the track axis. The LET of the ionizing radiation is shown to be a poor parameter for characterizing the Fricke dosi...

Effects of Track Structure on the Ion Radiolysis of the Fricke Dosimeter

Ionization energies of hyperlithiated Li2F molecule and LinFn−1 (n=3,4) clusters

Production of hyperlithiated Li2F by a laser ablation of LiF–Li3N mixture

The nascent rotational distributions of HCl (v=0, 1, and 2) generated in the photodissociation of three isomers of dichloroethenes (DCE) at 214 and 220 nm were measured under molecular beam conditions. HCl molecules were probed by a (2+1) resonantly enhanced multiphoton ionization technique combined with time‐of‐flight mass spectrometry. The rotational distributions of vibrationally excited HCl (v=1 and 2) molecules were Boltzmann‐type, while those of HCl (v=0) could not be represented by a Boltzmann distribution and consisted of two components. These results suggest that there are more than two processes in the photodissociation of DCE. Cl(2P3/2) and Cl*(2P1/2) could also be detected when DCE were photodissociated. The branching ratios of Cl*(2P1/2) to Cl(2P3/2) obtained in the present work were much larger than those obtained at 193 nm.

Katsutoshi Furukawa

Papers

Ionization energies of hyperlithiated Li2F molecule and LinFn−1 (n=3,4) clusters

Production of hyperlithiated Li2F by a laser ablation of LiF–Li3N mixture

The photodissociation dynamics of dichloroethenes at 214 and 220 nm

Radial dose distribution around a heavy ion's path

Predicted radiolysis yield in a Fricke solution irradiated with various heavy ions