Loading...
VAN DER WAALS FORCES This should prove to be the de?nitive work explaining van der Waals forces, how to calculate them and to take account of their impact under any circumstances and conditions These weak intermolecular forces are of truly pervasive impact, and bi-ologists, chemists, physicists, and engineers will pro?t greatly from the
Van der Waals (VDW) interactions are probably the most basic type of interaction imaginable Any two molecules experience Van der Waals interactions Even macroscopic surfaces experience VDW interactions, but more of this later The physical process that leads to Van der Waals interactions is clear, but it is difficult to
P1: IrK/IwX 0521839068pre CB776-Parsegian-FM December 26, 2005 19:38 VAN DER WAALS FORCES This should prove to be the de?nitive work explaining van der Waals forces, how
pot – due to attraction between the molecules (repulsion does not contribute to U pot in the model of colliding rigid spheres) The attraction forces result in additional pressure N2a/V2 The work against these forces atT = const provides an increase of U in the process of an isothermal expansion of the vdW gas: (see Pr 5 12) V Na vdW ideal
The existence of attractive forces between atoms was established by van der Waals on the basis of analysis of experimental data on equations of state of real gases It was F London who understood the electric nature of these forces and built in 1930 a seminal quantum-mechanical theory of the forces at large distances,
KEY WORDS: thermodynamics, van der Waals equation, phase transition, heat capacities, critical temperature 1 Introduction Many applications of thermodynamics are concerned with the behavior of ?uids and gases Thermodynamic properties, such as internal energy and enthalpy from which one calculates the heat and work requirements of industrial