  In this paper we present an approach for the generalization of adsorption of
light gases in porous materials. This new theory goes beyond the Langmuir and
BET theories, which are the standard approaches that have limited application
to crystalline porous materials by their unphysical assumptions on the amount
of possible adsorption layers. The derivation of the more general equation for
any crystalline porous framework is presented; the Restricted Multilayer Theory
(RMT). Our approach allows the determination of gas uptake considering only
geometrical constraints of the porous framework and the interaction energy of
the guest molecule with the framework. Based on this theory, we calculated
optimal values for the adsorption enthalpy at different temperatures and
pressures. We also present the use of this theory to determine the optimal
linker length for a topological equivalent framework series. We validate this
theoretical approach by applying it to Metal-Organic Frameworks (MOF) and show
that it reproduces the experimental results for 7 different reported materials.
We obtained the universal equation for optimal linker length given the topology
of a porous framework. This work applied the general equation to MOFs and H$_2$
to create energy storage materials, however this theory can be applied to other
crystalline porous materials and light gases, which opens the possibility of
designing the next generations of energy storage materials by first considering
only the geometrical constraints of the porous materials.
