Calculation and measurement of the second light-scattering virial coefficients of nonlinear molecules: a study of ethene

The second light-scattering virial coefficient B ρ of ethene has been extracted from measurements of the depolarization ratio ρ at gas pressures up to 3·2 MPa. The value calculated using our recent molecular tensor theory of B ρ for axially symmetric molecules, underestimates the experimental value by 40%. A complete molecular tensor theory of B ρ for nonlinear molecules is presented, and leads to a calculated value for ethene which is within 2% of the experimental value.