Question

As we will see later in this course, bond vibrations can bewell-approximated by
harmonic oscillators and molecular rotation can bewell-approximated by a rigid
rotor. Consider the ^1H^35Cl molecule, which has a bond length of127.45 pm, a bond-
vibration force constant of 516.3 N m-1, and individual atomicmasses of 1:007 8250
and 34:968 853.
When HCl is exposed to microwave radiation, it is found that the J= 1 ! J = 2
transition in HCl is more intense (occurs more often) than the J =0 ! J = 1
transition. Suggest a reason for this. (Hint: think about thedegeneracy of the
initial state for each transition.)