Direct time delay computation applied to the O + O exchange reaction at low energy: Lifetime spectrum of O species.

We report full quantum dynamical calculations for lifetimes of scattering resonances, among which are true metastable states, of the intermediate heavy ozone complex O of the O + OO reaction, for any value of the total angular momentum quantum number J. We show that computations for nonzero values of J are mandatory in order to properly analyze resonances and time delays, with a view to establish a somewhat comprehensive eigenlife spectrum of the complex O . Calculations have been performed in a given low to moderate energy range, including the interval between zero-point energies (ZPEs) of reagents and product species.

Extension of the Launay Quantum Reactive Scattering Code and Direct Computation of Time Delays.

Scattering computations, particularly within the realm of molecular physics, have seen an increase in study since the development of powerful quantum methods. These dynamical processes can be analyzed via (among other quantities) the duration of the collision process and the lifetime of the intermediate complex. We use the Smith matrix = -id/d calculated from the scattering matrix and its derivative with respect to the total energy.

First-Principles Computed Rate Constant for the O + O Isotopic Exchange Reaction Now Matches Experiment.

We show, by performing exact time-independent quantum molecular scattering calculations, that the quality of the ground electronic state global potential energy surface appears to be of utmost importance in accurately obtaining even as strongly averaged quantities as kinetic rate constants. The oxygen isotope exchange reaction, O + O, motivated by the understanding of a complex long-standing problem of isotopic ozone anomalies in the stratosphere and laboratory experiments, is explored in this context. The thermal rate constant for this key reaction is now in quantitative agreement with all experimental data available to date.

Quantum Dynamics of the O + O Collision Process.

We report full quantum integral and differential cross sections and rate constants for the O + O reactive process. This constitutes the first quantum scattering study of the OOO system. We emphasize the comparison with the O + O collision in close connection to the mass-independent fractionation (hereafter referred to as MIF) puzzle for ozone in atmospheric chemistry.

Differential Cross Sections and Product Rovibrational Distributions for (16)O + (32)O2 and (18)O + (36)O2 Collisions.

We report rotationally resolved opacity functions, product rotational distributions, and differential cross sections for the (16)O + (16)O(16)O (v = 0,j = 1) → (16)O(16)O (v' = 0,j') + (16)O and (18)O + (18)O(18)O (v = 0,j = 1) → (18)O(18)O (v' = 0,j') + (18)O collisions calculated by a time-independent quantum mechanical method employing one of the latest potential energy surface of ozone [ Dawes ; et al. J. Chem.

Quantum Dynamics of the (18)O + (36)O2 Collision Process.

We report full quantum cross sections and rate constants for the (18)O + (36)O2 → (36)O2 + (18)O collision process. This constitutes to the best of our knowledge the first dynamical study of the (18)O(18)O(18)O system, with three identical (18)O oxygen atoms. We emphasize the comparison with the (16)O + (32)O2 collision as this latter presents the exact same features as the one treated here, except the consistent change of mass for all three atoms.

Huge Quantum Symmetry Effect in the O + O2 Exchange Reaction.

We report extensive, full quantum-mechanical calculations for the (16)O + (16)O(16)O → (16)O(16)O + (16)O collisions, for both inelastic and atom exchange processes, using a time-independent method based on hyperspherical coordinates. The rates obtained in the present study are much larger than the previously reported ones for this system. The discrepancy is attributed to a huge symmetry effect that was missing in the studies so far.

A new post-quantization constrained propagator for rigid tops for use in path integral quantum simulations.

In this paper, we extend the previously introduced Post-Quantization Constraints (PQC) procedure [G. Guillon, T. Zeng, and P.

Probing the Superfluid Response of para-Hydrogen with a Sulfur Dioxide Dopant.

We recently presented the first attempt at using an asymmetric top molecule (para-water) to probe the superfluidity of nanoclusters (of para-hydrogen) [ Zeng , T. ; Li , H. ; Roy , P.

On the origin and convergence of a Post-Quantization Constrained propagator for path integral simulations of rigid bodies.

We present a new methodological procedure, based on Post-Quantization Constraints (PQC), to obtain approximate density matrices and energy estimators for use in path integral molecular dynamics and Monte Carlo simulations. The approach serves as a justification of the use of "RATTLE & SHAKE" type methods for path integrals. A thorough discussion of the underlying geometrical concepts is given.

Full dimension Rb2He ground triplet potential energy surface and quantum scattering calculations.

We have developed a three-dimensional potential energy surface for the lowest triplet state of the Rb(2)He complex. A global analytic fit is provided as in the supplementary material [see supplementary material at http://dx.doi.

Excited Li and Na in He(n): influence of the dimer potential energy curves.

The X(2)Σ ground and the A(2)Π and B(2)Σ first two excited states of Li-He and Na-He are determined using high level complete active space self-consistent field-multireference configuration interaction ab initio method. The obtained potentials differ from the ones proposed by Pascale [Phys. Rev.