THE REFRACTIVITY OF CO2 GAS IN THE REGION OF 10 MU-M

The refractivity of the CO//2 gas is measured with an experimental error of 2% in the 10- mu m region, using 10. 4- mu m band CO//2 laser line. The frequency of the CO//2 laser is swept through the Doppler profile of the laser line. The experiment is achieved using a 0. 63- mu m He-Ne/10. 6- mu m CO//2-laser interferometer with a 2-m long vacuum cell. From the result, it is found that the Koch's formula also holds for the wavelengths in the 10- mu m region within an accuracy of 2%.