  Although numerous investigations reveal the gas physisorption characteristics
of porous materials and a variety of theories have also established to describe
gas physisorption during the past century, the essence of physisorption
behavior of gas within nanoscale space is still indistinct. We find that the
physisorption behavior of complex molecular system of methane and carbon
dioxide within nanoporous materials exhibits a quantum effect. Based on this
quantum effect, we established a physisorption equation from the perspective of
quantum mechanics to re-understand the basic principles of gas physisorption
within nanopores. Energy level transition triggers gas physisorption, and
non-uniform spatial distribution of energy-quantized molecules within nanopores
dominates the gas physisorption behavior. The spatial distribution of gas
molecules can be adjusted by temperature, pressure and potential energy field.
This result contributes to understand and predict the physisorption behavior of
CH4 and CO2 within nanoporous materials.
