Total x-ray scattering by H2

From the Waller−Hartreee theory, the total x−ray scattering of H2 has been calculated with the first 10 natural orbitals of Davidson and Jones. Vibrational averaging has not been included. The calculated intensities differ by as much as 5% from a similar calculation with the Davidson and Jones SCF orbital. The accuracy of the calculations is demonstrated by agreement of 〈r12−1〉 from Tavard's sum rule with 〈r12−1〉 values given by Davidson and Jones. The coherent intensities from the first 10 natural orbitals are in close agreement with the SCF results. By correcting the calculated inelastic scattered intensities for relativistic effects, the total scattering intensities from the correlated wavefunction are in excellent agreement with the experimental values of Wollan. Corresponding SCF values are significantly different. The results for molecular hydrogen encourage us to suggest more accurate gas phase measurements of total x−ray scattering by other diatomic molecules in order to determine the two electron expectation 〈r12−1〉.