Measurement of molecular relaxation rates by IR-FIR double resonance spectroscopy (methanol laser)

It is shown how the rotational and vibrational relaxation rates of molecules, the latter of which limits the efficiency of optically pumped far-infrared lasers, can be measured by infrared-far-infrared double resonance spectroscopy. By measuring the gain line profile and amplitude as a function of the pressures of the laser gas and of additional different buffer gases present in the gain cell, the rate of molecular deexcitation processes can be determined. The results of the measurement of the pressure-broadening coefficients of the methanol 118.8 mu m wavelength line caused by collisions with methanol, SF/sub 6/, and He are presented.<
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