Dynamical importance of van der Waals saddle and excited potential surface in C( 1 D )+D 2 complex-forming reaction

It is commonly held that van der Waals wells are inevitable in chemical reactions. Here, the authors show that weak van der Waals forces in the entrance channel of a prototypical complex-forming reaction cause a van der Waals saddle instead, with different dynamical effects from a well at low collision energies.