Vibrational dependence of the H₂–H₂ <i>C</i>₆ coefficients

We use the sum-over-states formalism to compute the imaginary-frequency dipole polarizabilities for H₂, as a function of the H–H bond length, at the full configuration interaction level of theory using atom-centered d-aug-cc-pVQZ basis sets. From these polarizabilities, we obtain isotropic and anisotropic C₆ dispersion coefficients for a pair of H₂ molecules as functions of the two molecules’ bond lengths.