Cross-sections and rate coefficients for rotational excitation of aluminium hydroxide by helium

Abstract

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Rotational excitation of sodium hydroxide molecule (NaOH) by helium (He) at low temperature

“…Consequently, the linear approaches of helium atom (for θ=0°and θ=180°) lead to obtain two minima with different deeps where the deeper minimum is located toward the atom presented the highest positive value of charge distribution (Na atom for θ= 180°) in contrary to the T-shape approach (toward oxygen atom) where the exchange energy dominates. Furthermore, at θ=0°, the value of potential energy of interaction is in good agreement with the results obtained for the AlOH-He system at the same configuration [26,29]. Whereas, at θ=180°, NaOH-He and AlOH-He PESs do not have a similar behavior.…”

“…In order to generalize the behavior of rate coefficients for linear metal hydroxide molecules. We compare the computed rate coefficients of sodium hydroxide molecule induced by He with those from previous scattering calculations of aluminum hydroxide molecule [29].…”

Cross-section investigation of MgOH (X 2 Σ + ) fine-structure excitation by helium

“…Despite this, a repulsive behavior of the potential energy interaction is noted on the side of the Mg atom. Similar findings are observed for the AlOH-He interacting system, where a single minimum with a well depth of 32.68 cm −1 located at (θ = 0 • ; R = 8.2 bohr) on the side of the H atom was found [21]. However, in the case of the NaOH-He system two minima are found; a global minimum with a well depth of 100.15 cm −1 located at (θ = 180 • ; R = 7.8 bohr) on the side of the Na atom and a local minimum with a well depth of 21.94 cm −1 corresponding to the configuration (θ = 0 • ; R = 7.5 bohr) on the side of the H atom [22].…”

“…This observation is expected from radial terms, V λ (R), of the potential energy seeing as V 1 and V 3 are the most important coefficients in terms of magnitude (see section 2, figure 3). In fact, this propensity rule aspect is characteristic of metal hydroxide crosssections seeing that similar results are observed for AlOH and NaOH cross-sections, where odd Δ j processes are predominant [21,22]. Furthermore, when we compare transitions by pairs, for ΔN = 1 we have two transitions that correspond to Δ j = 0 and Δ j = 1; as clearly seen, the excitation associated with ΔN = Δ j = 1 (0 0.5 → 1 1.5 ) is favored compared to ΔN = 1 = Δ j = 0.…”