I am working on the derivation of the equation below for the difference in activation energies for the two reactions (1) and (2).
I've done the derivation, but I am unsure on some of the approximations I have used. When considering the activation energies I have just used the zero point energy for the C-H and C-D bonds - I am not sure why I can do that, but I assume its because the rest of the zero point energies cancel out.
Secondly I am confused why I can consider the transition states as isoenergetic, as to me they look like they would different energies.
Thank you for your help.