Four consecutive absorption lines in the pure rotational spectrum of gaseous 1h35cl are found to have the frequen- cies 2.50 × 1012, 3.12 × 1012, 3.74 × 1012, and 4.37 × 1012 s21.

calculate:

(a) the moment of inertia i of hcl (in kg m2)

(b) the energies of the j 5 1, j 5 2, and j 5 3 rotational levels of hcl, measured from the j 5 0 state (in joules)

(c) the hucl bond length (in angstroms)

(d) the initial and final j states for the observed absorp- tion lines