Pauli forces

Electrons with the same spin behave as if there is a repulsive force acting between them. This apparent force is sometimes called the Pauli force. However, it is preferable not to speak of Pauli forces, since they are only apparent forces, not real forces like electromagnetic or gravitational forces. In fact, the Pauli principle implies that there is an intimate interconnection between the constituent parts of matter in the universe. Strictly speaking, no part can be isolated from the rest, except in an idealized way. The Pauli force acts at any time and over huge distances, much larger than atomic dimensions, but its effect becomes dramatic only when electrons of the same spin happen to be close to each other. 

The Pauli "force" corresponds lo no interaction but results from the nature of quantum me-... 

Simons, G., and A. N. Bloch (1973). Pauli force model potential for solids. Phys. Rev. B7, 2754-61. 

The EDA results of the parent compounds show, that all three components of AEjn, vary parallel with the total interaction energy. Due to the larger TM- -H2 distance in Mo(CO)sH2, both the repulsive Pauli interaction and the attractive electrostatic and orbital interactions are considerably weaker in this complex. The larger decrease in the attractive interactions as compared to that in the Pauli forces leads to ca. 3 kcal/mol destabilization with respect to Cr(CO)5H2 and W(CO)5H2. On the other hand, the ratio of the electrostatic and orbital interactions, and that of the components of is rather... 

The glass transition is indicative of the cohesive energy within the salL which is decreased by repulsive Pauli forces... 

The answer is that the apparent solidity of matter is the result of Pauli forces. When your hand encounters the table top, the electrons in the atoms of your hand and the electrons in the atoms of the table top have the same spins and nearly the same energies. The Pauli principle ensures that these electrons cannot occupy the same regions of space, that the table top feels solid to your touch, even though Rutherford showed us that it is not. Were it not for the Pauli principle our apprehension of the world would be vastly different. 

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