Volume 119, Issue 18, 08 November 2003
Index of content:
State-selected and state-to-state photoionization study of trichloroethene using the two-color infrared-vacuum ultraviolet scheme119(2003); http://dx.doi.org/10.1063/1.1622932View Description Hide Description
By employing the two-color infrared (IR)-vacuum ultraviolet (VUV) laser photoionization (PI) schemes, we have determined the C–H stretching frequencies for trichloroethene and for On the basis of the IR-VUV-pulsed field ionization-photoelectron (PFI-PE) measurement, the ratio of the state-to-state PI cross section for to that for the formation of the ground state ion from the ground state neutral is determined to be 0.24. The VUV-PI efficiency (PIE) spectrum for and IR-VUV-PIE spectrum for show that the state-to-state PI cross section for the formation of in the ground state from is ≈0.006 that from in its ground state. As expected, the IR-VUV-PIE onset for exhibits less hot-band tailing than the VUV-PIE onset for supersonically cooled After taking into account the frequency, the ionization energy values for determined based on the IR-VUV-PIE and VUV-PFI-PE measurements are found to be in excellent agreement.
119(2003); http://dx.doi.org/10.1063/1.1623176View Description Hide Description
The radical–radical reaction dynamics of ground-state atomic oxygen with propargyl radicals has first been investigated by applying laser induced fluorescencespectroscopy in a crossed beam configuration, together with ab initio calculations. A new exothermic channel of was identified and the nascent distributions of OH reaction product in the ground vibrational state showed substantial rotational excitations with an unusual bimodal feature composed of the low- and high- components. No spin–orbit propensities were observed, whereas the averaged ratios of were determined to be With the aid of the CBS-QB3 level of ab initio theory it is predicted that on the lowest doublet potential energy surface the reaction proceeds through the addition complexes formed through the barrierless addition of to and that the counterpart of of the probed OH product is cyclopropenylidene On the basis of the comparison with statistical prior and rotational surprisal analyses, the ratio of population partitioning for the low- and high- regimes is estimated to be about 1:2 and the reaction is described in terms of two competing addition-complex mechanisms: a major short-lived dynamic complex in the high- regime and a minor long-lived statistical complex in the low- regime.
119(2003); http://dx.doi.org/10.1063/1.1623175View Description Hide Description
The photodissociationdynamics of state selected OD radicals has been examined at 243 and 226 nm using velocity map imaging to probe the angle–speed distributions of the and products. Both experiment and complementary first principle calculations demonstrate that photodissociation occurs by promotion of OD from high vibrational levels of the ground state to the repulsive state.