Abstract

We have used the powerful technique of THz time-domain spectroscopy¹ (TDS) to measure the absorption and dispersion of spectrally dense vapors of symmetric top molecules. Because of the high sensitivity and dynamic range of this technique we can observe extremely small contributions in the low frequency wing of the rotational absorption band which originate from the inversion of molecules due to collision induced tunneling between the two states of symmetry.

© 1998 IEEE