Chemical potential of an adsorbed species on equivalent sites
= Chemical potential of an adsorbed species on equivalent sites
{title2=$\mu_s=-\epsilon+k_BT\ln[\theta/((1-\theta)z_s)]$}
The occupied-to-vacant probability ratio of the <adsorption-site grand partition function> is $\theta/(1-\theta)=z_s e^{\beta(\mu_s+\epsilon)}$. Taking its <logarithm> yields the displayed <chemical potential>. <binding energy> and vibrational <energies> must share a consistent reference so that <zero-point energy> is not counted twice.