Perimetric coordinate system in potential energy surfaces, spline interpolations, and the study of triatomic reaction dynamics

• Published in: Theoretical chemistry accounts Vol. 133; no. 9
• Main Authors: Aoto, Yuri Alexando, Ornellas, Fernando R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2014
• Subjects: Atomic/Molecular Structure and Spectra; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Regular Article; Theoretical and Computational Chemistry; Potential energy surface; Splines interpolation; Pekeris coordinates; Perimetric coordinates sytem; Reaction dynamics
• ISSN: 1432-881X; 1432-2234
• DOI: 10.1007/s00214-014-1547-9

Two applications of the perimetric coordinates to triatomic potential energy surfaces are explored. The first is the depiction of level surfaces, providing a global visualization of the potential energy surface. In this representation, the relation among the stationary points and the dissociation channels are easily seen. These level surfaces are shown to be the natural generalization of the well-known two-dimensional level curves of restricted potential energy surfaces; they also allow us to understand the relation of the two-dimensional graphs with the global potential energy surface. Case studies for [Cl, H 2 ], [H, O, Cl] and [O 3 ] potential energy surfaces are discussed in detail. The second application of the perimetric coordinates is the construction of global potential energy surfaces by means of cubic splines, thus avoiding the restrictions related to the triangular inequality. The procedure is straightforward, and a careful analysis of the influence of the interpolation knots on the quality of the potential energy surface was carried out. The potential energy surfaces constructed by such procedure were able to reproduce known dynamical features of the following chemical reactions: Cl + H 2  → H + HCl, F + HD → HF(DH) + D(H) and O( 1 D) + HCl → Cl + OH (H + OCl).