Dipole properties of molecular nitrogen

Experimental data on optical absorption, electron scattering and optical refractivity are used to construct a model dipole spectrum of molecular nitrogen which is consistent with the oscillator strength sum rule. The spectrum is used to calculate various dipole properties. The spherically symmetric van der Waals coefficient for a pair of nitrogen molecules is 73.4 A.U., the mean excitation energy describing the slowing down of fast particles is 82.1 eV and the Rayleigh scattering cross section at Lyman α is 5.6 × 10 -24 cm 2 . The vibrational Raman scattering at Lyman α is estimated to lie between 10 -27 and 10 -26 cm 2 .