Krypton's tabulated electronic polarisability volume is

PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Electric fields in matter · Electric fields in matter

The Boundary-Value Problem, Ch Molecular polarisability, permanent dipoles and the Clausius-Mossotti relation

Problem

\alpha/4\pi\varepsilon_0 = 2.48\times10^{-30}\,\mathrm{m^3}

. Independent measurements give an atomic radius for krypton of about

130\,\mathrm{pm}

. ((a)) Using the uniform-ball model (a point nucleus inside a uniform ball of electron charge of radius

a

), estimate the effective radius

a

implied by the tabulated polarisability, and compare it with

130\,\mathrm{pm}

. ((b)) Krypton gas at

1.000\,\mathrm{atm}

and

293\,\mathrm{K}

may be treated as an ideal gas. Estimate the fractional local-field correction

\chi_e/3

to the field acting on one atom, and say whether it is significant.