One potential energy curve, many isotopologues
Under the Born–Oppenheimer approximation H₂, HD and D₂ share the same Morse-like curve E(R) (blue). Only the vibrational levels (red) shift, because the nuclear masses differ.
Under the Born–Oppenheimer approximation H₂, HD and D₂ share the same Morse-like curve E(R) (blue). Only the vibrational levels (red) shift, because the nuclear masses differ.