Order—Geometric Space Configuration of Momentum and Thermal Potential Energy

Maxwell had advanced the famous velocity distribution law for ideal gas and idea of momentum space. But he had also put the problem about “Maxwell demon” to oppugn that if should the space configuration of momentum exist? This paper defines the pressure resulting from elastic collision based on no-wall space model of ideal gas under the thermodynamic equilibrium. It lets the presupposition about Maxwell velocity space without any actions to be untenable. There are space configurations of momentum for ideal gas whatever in no-wall space or in box with solid wall that is a restriction for order relating space configuration of position of particle. The order and Boltzmann entropy should account for momentum space configuration. This paper proposes a statistic method for local certain region of non-localized particles of ideal gas. The pV and −TS are argued to be two kinds of potential energy. The −TS is the heat potential energy inside of an isolation system which change is equal to the heat exchanging between the system and surrounding.