Relationship between photoisomerization path and intersection space in a retinal chromophore model

J Am Chem Soc. 2003 Mar 5;125(9):2804-8. doi: 10.1021/ja027352l.

Abstract

A low-lying segment of the intersection space (IS) between the excited-state and the ground-state energy surfaces of a retinal chromophore model has been mapped using ab initio CASSCF computations. Analysis of the structural relationship between the computed IS cross-section and the excited state Z --> E isomerization path shows that these are remarkably close both in energy and in structure. Indeed, the IS segment and the Z --> E path remain roughly parallel and merge only when the double bond reaches a 70 degree twisting. This finding supports the idea that, in certain chromophores, a more extended segment of IS, and not a single conical intersection, contributes to the decay to the ground state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Isomerism
  • Models, Chemical*
  • Photochemistry
  • Retinaldehyde / chemistry*
  • Thermodynamics

Substances

  • Retinaldehyde