G. Reisfeld et U. Asaf, RELATION BETWEEN THE ELECTRON-SCATTERING LENGTH AND THE VAN-DER-WAALSAPPROXIMATION TO THE EQUATION OF STATE, Physical review. A, 49(1), 1994, pp. 348-349
A theoretical relation between the electron scattering length and the
van der Waals approximation to the equation of state is described. The
theory provides a simple calculation for the scattering length of neu
tral atomic scatterers such as rare gases, using two experimental para
meters: the hard-core radius (calculated from the van der Waals equati
on of state, using critical data) and the atomic polarizability. The r
esults' for the calculated electron scattering length agree with measu
red values derived either from the energy shifts of highly excited mol
ecular Rydberg states, perturbed by He, Ne, Ar, Kr, and Xe, or from sw
arm electron cross-section data for the same gases.