Ozone Photodissociation in the Singlet Channel at 226 nm.

We report the rotational state distribution and vector correlations of the O(a Δ, = 0) fragments arising from the 226 nm photodissociation of jet-cooled O. Consistent with previously reported trends, the rotational distribution is shifted to higher rotational states with decreasing wavelength. We observe highly suppressed odd rotational state populations due to a strong Λ-doublet propensity.

Imaging inelastic scattering of CO with argon: polarization dependent differential cross sections.

Rotationally inelastic scattering of carbon monoxide (CO) with Argon at a collision energy of 700 cm-1 has been investigated by measuring polarization dependent differential scattering cross sections (PDDCSs) for rotationally excited CO molecules using a crossed molecular beam apparatus coupled with velocity-map ion imaging. A simple and robust (1 + 1' + 1'') VUV (Vacuum Ultra-Violet) REMPI (Resonance Enhanced Multi Photon Ionization) scheme is used and images are obtained by setting the VUV light polarization direction parallel or perpendicular to the scattering plane. Clear differences between the images for the two polarizations are observed, indicating strong collision induced alignment of the rotational angular momentum of scattered CO.

Nascent O ( Δ, = 0, 1) rotational distributions from the photodissociation of jet-cooled O in the Hartley band.

We report rotational distributions for the O ( Δ) fragment from the photodissociation of jet-cooled O at 248, 266, and 282 nm. The rotational distributions show a population alternation that favors the even states, as previously reported for a 300 K sample by Valentini [J. Chem.

Photodissociation dynamics of OCS near 214 nm using ion imaging.

The OCS photodissociation dynamics of the dominant S((1)D2) channel near 214 nm have been studied using velocity map ion imaging. We report a CO vibrational branching ratio of 0.79:0.

Product angular distributions in the ultraviolet photodissociation of N2O.

The angular distribution of products from the ultraviolet photodissociation of nitrous oxide yielding O((1)D) and N(2)(X Σ(g)(+)(1)) was investigated using classical trajectory calculations. The calculations modeled absorption only to the 2(1)A(') electronic state but used surface-hopping techniques to model nonadiabatic transitions to the ground electronic state late in the dissociation. Observed values of the anisotropy parameter β, which decrease as the product N(2) rotational quantum number j increases, could be well reproduced.

Photodissociation of ozone in the Hartley band: Product state and angular distributions.

Product state properties from the photodissociation of ozone in the ultraviolet Hartley band are investigated by trajectory surface-hopping calculations. The diabatic B and R state potential energy and coupling surfaces of Schinke and McBane [J. Chem.

Rovibrational energy transfer in Ne-Li2(A1Sigmau+,v=0): Comparison of experimental data and results from classical and quantum calculations.

Absolute rate constants for rotational and rovibrational energy transfer in the system Ne-Li2(A1Sigmau+) were measured by a dispersed fluorescence technique following excitation of the (v = 0,j = 18) initial level of Li2(A1Sigmau+). The rate coefficients for Deltav = 0 processes decline monotonically with increasing |Deltaj|. The Deltav = 1 rate coefficients are also peaked near Deltaj = 0 but show a broad shoulder extending to approximately Deltaj = 30.

An exchange-Coulomb model potential energy surface for the Ne-CO interaction. II. Molecular beam scattering and bulk gas phenomena in Ne-CO mixtures.

Four potential energy surfaces are of current interest for the Ne-CO interaction. Two are high-level fully ab initio surfaces obtained a decade ago using symmetry-adapted perturbation theory and supermolecule coupled-cluster methods. The other two are very recent exchange-Coulomb (XC) model potential energy surfaces constructed by using ab initio Heitler-London interaction energies and literature long range dispersion and induction energies, followed by the determination of a small number of adjustable parameters to reproduce a selected subset of pure rotational transition frequencies for the (20)Ne-(12)C(16)O van der Waals cluster.

CO blocking of D2 dissociative adsorption on Ru(0001).

The influence of pre-adsorbed CO on the dissociative adsorption of D(2) on Ru(0001) is studied by molecular-beam techniques. We determine the initial dissociation probability of D(2) as a function of its kinetic energy for various CO pre-coverages between 0.00 and 0.

A hierarchical family of three-dimensional potential energy surfaces for He-CO.

A hierarchical family of five three-dimensional potential energy surfaces has been developed for the benchmark He-CO system. Four surfaces were obtained at the coupled cluster singles and doubles level of theory with a perturbational estimate of triple excitations, CCSD(T), and range in quality from the doubly augmented double-zeta basis set to the complete basis set (CBS) limit. The fifth corresponds to an approximate CCSDT/CBS surface (CCSD with iterative triples/CBS, denoted CBS+corr).

State-to-state rotational rate constants for CO + He: infrared double resonance measurements and simulation of the data using the SAPT theoretical potential energy surface.

An extensive data set of 54 time-resolved pump-probe measurements was used to examine CO + He rotational energy transfer within the CO v = 2 rotational manifold. Rotational levels in the range Ji = 2-9 were excited and collisional energy transfer of population to the levels Jf = 1-10 was monitored. The resulting data set was analyzed by fitting to numerical solutions of the master equation.

State-to-state rotational relaxation rate constants for CO+Ne from IR-IR double-resonance experiments: comparing theory to experiment.

IR-IR double-resonance experiments were used to study the state-to-state rotational relaxation of CO with Ne as a collision partner. Rotational levels in the range Ji=2-9 were excited and collisional energy transfer of population to the levels Jf=2-8 was monitored. The resulting data set was analyzed by fitting to numerical solutions of the master equation.