Evidence for reaction mechanisms (Hydrogen bromide and oxygen)

What do we mean by reaction mechcanisms? There are plenty of examples on this page that could be shown - if data was plotted

http://www.chem1.com/acad/webtext/dynamics/mech.html

Reaction of atomic oxygen with hydrogen bromide - spectral evidence show which intermediates are present.

https://digitalarchive.rit.edu/xmlui/handle/1850/2262

 
This is new version