Molecular Structure of Dicyclopentadiene by Gas‐Phase Electron Diffraction and Theoretical Calculations

ABSTRACT In this article, the structure of the free dicyclopentadiene (DCPD) molecule was studied for the first time by the gas‐phase electron diffraction (GED) at 268 K supplemented by quantum chemical calculations (B3LYP and MP2 with the cc‐pVTZ basis set). The possibility of transition between endo and exo isomers of DCPD was considered in the gas phase. Three models of the refinement of the experimental (GED) data were applied on the base of two harmonic force fields and molecular dynamic simulations. The theoretical and experimental geometric parameters of the endo isomer are presented. In addition, the geometric parameters of the exo isomer calculated by quantum chemistry are given.