Elementary Processes in Atmospheric Chemistry: Quantum Studies of Intermolecular Dimer Formation and Intramolecular Dynamics

Potential energy surfaces for van der waals complexes of rare gases with H2S and H2S2: Extension to xenon interactions and hyperspherical harmonics representation

“…These analytical representations of the potential energy surfaces can be used in classical and reduced quantum scattering studies. In particular the interactions of rare gases with the floppy molecule H 2 S 2 is of relevance for simulations of chiral effects in molecular collisions 4, 6, 8–18.…”

“…As in previous works on simpler systems, we have exploited hyperspherical harmonics as the proper orthonormal expansion basis set for the manifold spanned by the specific range of angular variables 6, 4–24. The five body system H 2 O‐H 2 is a typical non‐linear‐molecule–linear‐molecule case 25 and its interaction potential can be expressed as a function of five variables (Fig.…”

“…For molecular dynamics studies, in particular for the quantum mechanics ones (possibly requiring freezing of some degrees of freedom inactive in specific problems) we propose here representations of potential energy surfaces, extending to H 2 S 2 ‐Xe an expansion in terms of hyperspherical harmonics previously used for the other rare gases 4. The expansion treats as rigid the intermolecular bonds, but includes flexibility in the torsional mode, as of perspective use in the modeling of chirality changing mechanisms due to molecular collisions 4, 8–18. For the H 2 S‐Rg systems, a minimal model of hyperspherical expansion is presented and discussed, as of potential applicability also for the important H 2 O‐Rg cases, possibly requiring extensions to additional leading configurations.…”

Quantum chemical and dynamical approaches to intra and intermolecular kinetics: The CnH2nO (n = 1, 2, 3) molecules

“…These problems arise in connection with experimental progress in the study of elementary processes, and are often motivated by their occurrence in the modeling of a wide spectrum of phenomena. Recent work in this laboratory concerned molecules containing peroxidic and persulfidic bonds1–6, characterizing the effect of substituents, and specifically considering processes of chirality changing isomerization by torsion. Here, we are interested in investigating systematically a sequence of other oxygen containing organic molecules of general formula C n H 2 n O, where n = 1, 2, and 3.…”

“…They also offer the perhaps simplest and neatest paradigm of chirality changing processes, placing them under focus for the paramount interest that is involved in these issues16. The interesting processes of large amplitude vibrations, such as the chirality change transitions associated with the torsional motions around the OO and SS bonds, stimulated the previous quantum chemical studies in view also of their roles in biological and combustion chemistry, and in particular in the photochemistry of the minor components of the atmosphere2, specifically hydrogen peroxide3. Further studies regarded several systems obtained by substitutions of the hydrogens in H 2 O 2 by alkyl groups4 or halogens5.…”