Comment on "elimination of translational and rotational motions in nuclear orbital plus molecular orbital theory" [J. Chem. Phys. 122, 164101 (2005)]

In moving-nuclei calculations on some simple diatomics and on water, Nakai [J. Chem. Phys.122, 164101 (2005)] extend their earlier translation-free nuclear orbital plus molecular orbital (TF-NOMO) theory, in which the translational part of the Hamiltonian is subtracted from the full Hamiltonian, to a translation- and rotation-free approach, in which a rotational term is subtracted from the TF-NOMO Hamiltonian. It is suggested that the chosen rotational term is not unique and is not valid over all regions of space.