thermomolecular pressure difference

Thermomolecular pressure is the difference in pressure that arises from thermal transpiration. Thermal transpiration is a phenomenon where a gas moves from a colder region to a warmer region, or vice versa, due to a temperature difference across a porous barrier or a narrow tube. This movement creates a pressure imbalance.1

Vapour pressure, on the other hand, is the pressure exerted by a substance in its gaseous state when it is in equilibrium with its liquid or solid form. This pressure increases with temperature and is related to a substance's tendency to transition into a vapour state.2