Is there a way to distinguish the different types of interactions from NCI plots? Is an analysis described in J. Am. Chem. Soc. 2010, 132, 18, 6498–6506 possible with Q-Chem?
I believe that the NCI plot option in Q-Chem is simply plotting the reduced density gradient. The color-coding in that paper comes from eigenvalues of the Laplacian.
For a developer, this could be implemented by evaluating the Laplacian on the XC grid, which of course we have, e.g., for meta-GGA functionals.