Is the bond length in HCl the same as that in DCl? The wavenumbers of the J = 0  1 rotational transitions for H35Cl and 2H35Cl are 20.8784 and 10.7840 cm–1, respectively. Accurate atomic masses are H = 1.007825 amu, 2H = 2.0140 amu, and 35Cl = 34.96885 amu. Based on this information alone, can you conclude that the bond lengths are the same or different in the two molecules?