ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An analysis of molecular shape has been performed along an ab initio reaction path of the PPO → OPP isomerization. In a first approximation, we have used the fused-sphere (van der Waals) model to represent shape. The results show that there is no one-to-one correspondence between the species defined in terms of shape and those based on an energy criterion. In contrast to the cases of most other isomerizations in triatomic molecules (e.g., the HCN isomerization), for the PPO isomerization there exists a stable intermediate. For the elementary reaction from the linear PPO (C∞v, reactant) to the cyclic P2O (C2v, intermediate), we found no distinct molecular shape type for the transition structure (between the reactant and the intermediate). In terms of shape, the nuclear configuration of the transition structure is more similar to that of the intermediate than that of the reactant. Using the PPO → OPP reaction as an example, in this work we discuss the implications of this result regarding possible measures of shape similarity and shape stability along reaction paths. We have performed a molecular-shape analysis of the electron density contour surfaces to test the reliability of the fused-sphere approximation. A comparison between the van der Waals and electron isodensity surface models at critical points shows that the former model can be qualitatively correct for molecular-shape descriptions along some reaction paths.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560420308
