The bond distance for HCl is 1.29 A. At the lowest rotational state the energy is zero. What is the energy and angular momentum Lz corresponding to the first nonzero rotational state? I m not sure if I am approaching this problem right. first I did 1.2 A = 8.3 x 10^7 cm^-1 Then I used this equation for energy because HCl has characteristic of diatomic molecule. E = (v cm^-1)hc100 is this right?