Unveiling shape resonances in H + HF collisions at cold energies

By aligning the reactant's rotational angular momentum it is possible not only to enhance or to diminish the intensity of the resonance, but also to split the resonance peak, disentangling the underlying contributions to the resonance pattern.

Analytical model for computing translational and rotational angular momentum occurring in treadmill walking

The kinematical modifications of human gait associated with treadmill walking are well studied in the literature. Fewer researches are focusing on computing the dynamical parameters of the gait, in this particular situation. Starting from kinematical data recorded in treadmill walking, the paper proposes an analytical model of the lower limbs that allows computation of translational and rotational angular momentum for each segment. The experimental data used in the study were recorded using ultrasound based, 3D motion equipment. By mean of this system, relative and absolute angles of the lower limb can be computed using Cartesian coordinates of each anatomical landmark. The velocities and accelerations were obtained by numerical derivative. In order to compute the dynamical parameters, segment masses and inertias were collected from the literature. The masses are based on percentage of total body weight while the segment inertias are based on geometrical characteristics of lower limb segments.

QUASICLASSICAL TRAJECTORY STUDY OF STEREODYNAMICS FOR THE REACTIONS Li+HF/DF/TF

Stereodynamics of the reaction Li + HF (v = 0,j = 0) → LiF + H and its isotopic variants on the ground electronic state (12A′) potential energy surface (PES) are studied by employing the quasiclassical trajectory (QCT) method. At a collision energy of 2.2 kcal/mol, product rotational angular momentum distributions, P(θr) and P(ϕr), are calculated in the center-of-mass (CM) frame. The results demonstrate that the product rotational angular momentum j′ is not only aligned along the direction perpendicular to the reagent relative velocity vector k, but also oriented along the negative y-axis. The four generalized polarization-dependent differential cross sections (PDDCSs) are also computed. The PDDCS00 distribution shows a sideways scattering for the reaction Li + HF and a strongly backward scattering for the reaction Li + DF . However, it displays both the forward and backward scatterings for the reaction Li + TF . These features demonstrate that the Li + HF and Li + DF reactions proceed predominantly through the direct reaction mechanism. However, the Li + TF reaction undergoes both the direct and indirect reaction mechanisms. The PDDCS21- distribution indicates that the product angular distributions are anisotropic.

A QUASSICLASSICAL TRAJECTORY STUDY OF THE REACTANT STATE RESOLVED STEREODYNAMICS OF THE REACTION C + OH(v,j) → CO + H

Quassiclassical trajectory (QCT) calculations have been performed for the radical–radial reaction C + OH (v,j) → CO + H on the ab initio potential energy surface of [Zanchet et al., J. Phys. Chem. A110: 12017, 2006] in order to study the stereodyanmics of the title reaction. The product rotational angular momentum (j′) polarization in the (k,k′) scattering frame has been determined for selected rovibrational state of OH at the collision energies from 0.05 eV to 1.0 eV. The j′ distribution of product CO is found to display both alignment and orientation. Furthermore, the j′ in the k – k′ scattering frame were found to be very sensitive to the reactant OH rotational state, but not sensitive to the reactant OH vibrational state.