Adsorbate cross-sectional areas

Abstract

Using the BET equation to determine W _m, the monolayer weight, and with reasonable estimates of the adsorbate cross-sectional area, A the total sample surface area, S _t, in square meters, can be calculated from equation (4.13).

$${S_t} = \frac{{{W_m}\bar NA}}{{\bar M}} \times {10^{ - 20}}{m^2}$$

((cf.4.13))

with W_m in grams, $\bar M$ is the adsorbate molecular weight, $\bar N$ is Avogadro’s number (6.02 × 10²³ molecules per mole) and A in square ångströms per molecule. Division by the sample weight converts S_t to S, the specific surface area.