[oscillate_wildly]

(f) The rotational energy levels of a HCl molecule are given by the following equation:
  ε  =  B J (J + 1)
 
where B has a value of 2.10×10^-22 joules.
 
(i) Calculate the separation in energy of the lowest two rotational levels of this
molecule, and hence determine the wavelength of light required to cause a molecule
to be excited from the lower to upper energy level.  [6 marks]

I worked out that photon energy (E) = 4.20 x 10^-22
And that the wavelength = 4.730 x 10^-4

For J, I used 0 and 1 as they are the lowest two rotational levels.

(ii) For the same two energy levels, and using the equation for the Boltzmann
distribution, calculate the value for the ratio of the populations of the upper and
lower energy levels, (Nupper /Nlower ), at room temperature (25°C), given that the
degeneracy of each level is  g =  (2J + 1).  [6 marks]

I can't seem to work this one out.

I know that the boltzman distribution is  N₂/N₁ = g₂/g₁ exp (-delta E/kT)

But every time I attempt to work it out I keep getting zero. Anyone know how to do this one? Thanks.

[zxt]

(f) The rotational energy levels of a HCl molecule are given by the following equation:
  ε  =  B J (J + 1)
 
where B has a value of 2.10×10^-22 joules.
 
(i) Calculate the separation in energy of the lowest two rotational levels of this
molecule, and hence determine the wavelength of light required to cause a molecule
to be excited from the lower to upper energy level.  [6 marks]

I worked out that photon energy (E) = 4.20 x 10^-22
And that the wavelength = 4.730 x 10^-4

For J, I used 0 and 1 as they are the lowest two rotational levels.

(ii) For the same two energy levels, and using the equation for the Boltzmann
distribution, calculate the value for the ratio of the populations of the upper and
lower energy levels, (Nupper /Nlower ), at room temperature (25°C), given that the
degeneracy of each level is  g =  (2J + 1).  [6 marks]

I can't seem to work this one out.

I know that the boltzman distribution is  N₂/N₁ = g₂/g₁ exp (-delta E/kT)

But every time I attempt to work it out I keep getting zero. Anyone know how to do this one? Thanks.

g1=1,g2=3, :delta:E=2B Joules, T=298.15K. Did you calculate like this? If you did so, I don't figure out any wrong.