[babyruth789]

The energy of a vibrating molecule is quantized much like the energy of an electron in the hydrogen atom. The energy levels of a vibrating molecule are given by the equation
En = (n+1\2) hv
where n is a quantum number with possible values of 1,2 ... and where v is the frequency of vibration. The vibration frequency of HCl is approximately 8.85*10^13 s-1.

What minimum energy is required to excite a vibration in HCl? 

What wavelength of light is required to excite this vibration?

I know that once I find the minimum energy I will be able to find the wavelength. I can use the equation given in the problem, I am given everything, but how do I know what the quantum number is for HCl? (n)

[renge ishyo]

It wants the minimum energy, so what is the smallest value of n that you can plug into your equation?