Abstract
The Hg—H2 collision complex in the reaction Hg 3P1 + H2 has been investigated by a
new method involving the Van der Waals complex of the reactants. This method yields
the first observation of a vibrational transition in a reactive collision complex. Furthermore
the fixed geometry of the Van der Waals complex corresponding to the Hg 3P1
state enables the separation of two different reaction paths depending on the electronic
configuration of the complex, namely