Answer:
 ΔE = h f
Step-by-step explanation:
The energy for a quantum harmonic oscillator is given by the expression 
 
 E = (ν + ½) h f 
 
where ν is an integer and ½ is the ground state energy and zero point, 
 
In this case, if the emission frequency is f, the position between the initial (excited) and final (ground state) states is 
 
 DE = (v_f- v₀) hf 
 
the minimum emitted frequency is 
 v_f = 1 
 v₀ = 0
 
 ΔE = h f