Solution
= Solution
The quantities $f_A$ and $f_B$ are molecular <partition functions> per unit <volume> for the two reactants, with their internal rotational, vibrational and electronic factors included. Thus their translational factors are $(2\pi m_jkT/h^2)^{3/2}$, rather than those factors multiplied by $V$. Their energy zeros must match the separately displayed barrier convention.