Compton profiles and other momentum-space properties ofN2

Various momentum-space properties of ${\mathrm{N}}_2$ in its ground electronic state (X ${\mathrm{}}^1$ ${\Sigma }_g^{+}$) are computed from a wave function substantially more accurate than those previously used for such purposes. The wave function was obtained by first-order configuration interaction (CI) relative to a full valence multiconfiguration self-consistent-field reference wave function constructed from a large basis set of Slater-type functions. The calculated isotropic Compton profile agrees best with 160-keV γ-ray experiments and with a previous CI calculation. The calculated values of 〈$p^k$〉 (-2≤k≤4) agree well with values obtained from 25-keV electron-impact experiments. The value and second derivative of the spherically averaged momentum density at p=0 are not quite as sensitive to details of electron correlation as had been thought previously. Anisotropic properties such as directional Compton profiles parallel and perpendicular to the bond and the J(0,γ) surface are also calculated; however, calculations with a larger basis set will be required to obtain converged values of these anisotropic properties.