Inelastic collision dynamics of oriented NO molecules with Kr atoms

Abstract

Building on our previous work on NO + Ar, this paper presents a complete set of orientation measurements and quantum mechanical calculations for the NO + Kr collision system, including both spin-orbit conserving and changing collisions, and both side-on (x-axis) and end-on (z-axis) orientations. While many of the trends observed in the oriented differential and integral scattering distributions, as well as in the spin-orbit branching fractions, are similar to the ones seen previously for NO + Ar, a direct comparison with the Ar data reveals subtle differences in the scattering dynamics, which we rationalise with the more extended attractive regions on the NO + Kr potential energy surfaces. High-impact parameter collisions that lead to low scattering angles in the spin-orbit conserving manifold are particularly sensitive to the topology in the attractive parts of the potential, whereas more impulsive, low-impact parameter trajectories, which sample the repulsive parts of the potential, produce very similar features in the oriented differential cross sections for the Ar and Kr systems, especially for spin-orbit changing collisions.

Low-temperature reaction dynamics of paramagnetic species in the gas phase

“…Stark decelerators and electrostatic hexapole guides have also been successfully utilised in the manipulation of radicals that also possess an electric dipole moment (such as OH and NO), with a number of inelastic scattering studies reported. 62–66 A magnetic hexapole guide has also been adopted for crossed beam inelastic scattering studies involving paramagnetic N 2 (A 3 Σ u + ) and NO(X 2 Π). Through the application of an additional magnetic field to align the metastable N 2 reactants after they exited the hexapole, the effect of stereodynamics on the probability of energy transfer was explored.…”

Quantum stereodynamics of cold molecular collisions

“…The stereodynamics of inelastic collisions with open-shell molecules has been widely explored, especially for collisions involving OH or NO in which the internuclear axis was oriented using hexapole and orienting fields, leading to the measurement of the integral steric asymmetry. [101][102][103][104][105][106] More recently, a major breakthrough was achieved with the measurements of state-to-state differential cross section for oriented NO molecules with rare gases, 58,60,[107][108][109][110][111] allowing the determination of both differential and integral steric effects. It was shown that by changing the direction of the orienting field with respect to the relative velocity, a remarkable control could be exerted over the branching between the spin-orbit changing and the spin-orbit conserving rotational product channels.…”

When experiment challenges theory: Scattering of vibrationally excited molecules in the cold collision energy regime

“…9,11,25,26 More than that, the orientation and alignment of the scattered (outgoing) NO molecules could be measured as a function of the scattering angle [27][28][29][30] and, quite recently, the effects of orientation of the reactant (incoming) NO molecules on the differential cross section in collisions with Rg, mostly Ar, could be established. [31][32][33][34][35] On the theory side, quantum mechanical close coupling (QMCC) scattering calculations on accurate two-dimensional ab initio PESs using the benchmark coupled-cluster, CCSD(T), method with the NO internuclear distance fixed at its equilibrium value 36 were performed and found to account for all the details revealed by the experiments. Although state of the art, most of these experiments except for those described in Refs.…”