Abu’s paper has been published in Molecular Physics! In this study, we take the formulation of vibrational heat-bath configuration interaction by the Berkelbach group and implement an alternative formulation by explicitly calculating and storing all Hamiltonian matrix elements. Like a lot of quantum chemistry methods, which one of the formulations is best seems to depend on the system and the level of accuracy required. Our technique appears to work better for ethylene oxide, while the previous formulation does better for naphthalene. Link is here.