For an atom, such as a hydrogen atom, then f = 3 , because an atom can move in three different, orthogonal directions. Consequently, κ κ = 0.2 . If the hydrogen atom is ionized, i.e., it is a proton, and is in a strong magnetic field then f = 2 , because the proton can move along the magnetic field and rotate around the field lines. In this case, κ κ = 0.25 . A diatomic molecule, e.g., a hydrogen molecule, has f = 5 and κ κ = 1 / 7 ≈ ≈ 0.143 . For a non-linear triatomic molecule, such as water, f = 6 and κ κ = 0.125 . If f becomes very large, then κ κ approaches zero. This is summarised in the Table 1, where we see that different gases may have different gravitational radii.