1. Microwave Spectrometer
The radiation from the source passes through a gaseous sample and is detected
by a crystal diode detector that is followed by an amplifier and display system
(chart recorder).

2. Varian’s First Klystron

3. Fourier Transform Microwave Spectrometer
… the radiation is confined in an evacuated cavity between a pair of spherical mirrors
and the sample is introduced by a pulsed nozzle that lowers the temperature of the
sample to less than 10 K. The sample is subjected to rotational energy excitation by
application of a pulsed microwave signal, and the resulting emission signal is detected
and Fourier-transformed to an absorption versus frequency spectrum.

4. Spectrum for HCl - Far IR

5. Fundamental Line for HCl

6. Vibration-Rotation Spectrum for Diatomic Mols.

7. Vibration – Rotation Spectrum of HCl in the Near IR

8. Types of Tops

9. Prolate vs. Oblate Tops

10. Emission Microwave Spectrum in Orion A

11. Search for HOC+