THE MEASUREMENT OF ABSOLUTE ABSORPTION INTENSITIES WITH A STARK-MODULATED MICROWAVE SPECTROGRAPH
HARVARD UNIV CAMBRIDGE MA MALLINCKRODT LAB
Pagination or Media Count:
The method developed by D. H. Baird and G. R. Bird for the measurement of relative absorption intensities with the Stark-modulated microwave spectrograph was extended to the measurement of absolute absorption intensities. The determination of absolute intensity is based on the measurement of the ratio of modulation-frequency component to direct component of crystal current at several microwave power levels and the extrapolation of the ratio to zero power. The method was tested on the line CH3CL35JO 1, F32 52 with measured intensities 15 less than the calculated intensity being obtained over a range of 250 in microwave power. Measurements at very low powers are prevented by the presence of a small amount of pickup in the crystal circuits from the square wave generator. Since other sources of error are present, notably multiple reflections in the absorption cell, the uncertainty of this method cannot be evaluated as well as would be desirable. It is not greater than 25 for medium intensity lines, and this is adequate for the identification of asymmetric rotor lines.
- Atomic and Molecular Physics and Spectroscopy