1. How do I get experimental information on bond lengths in simple
Molecules?
(A) Vibrational spectra
(B) UV/vis spectra
(C) Microwave spectra
(D) Fluorescence spectra

2. How do I get experimental information on bond lengths in simple
Molecules?
(A) Vibrational spectra … No. I mostly get force constants here.
(B) UV/vis spectra … No. Electronic spectra carry little direct structural information.
(C) Microwave spectra … YES! Rotational constants carry bond length information!
(D) Fluorescence spectra … No. Just another form of electronic spectrum.

3. Based on the selection rule for a purely rotational transition, DJ=±1,
how does does a rotational spectrum look?
(A) A series of equally spaced peaks.
(B) A series of peaks with decreasing difference in frequency.
(C) Just one peak, because DJ is always ±1.
(D) A series of peaks with increasing difference in frequency. n n n

4. Based on the selection rule for a purely rotational transition, DJ=±1,
how does does a rotational spectrum look?
(A) A series of equally spaced peaks.
(B) A series of peaks with decreasing difference in frequency.
(C) Just one peak, because DJ is always ±1.
(D) A series of peaks with increasing difference in frequency. n n n