Collision‐induced spectral measurements with a long path cell and a laser source

Laser measurements at 23.13 cm−1 of collision‐induced absorption are described using absorption cells over 1500 cm in length and a liquid‐helium‐cooled bolometer. Also reported are a number of improvements over a previously described system operating at different laser frequencies. The improvements are related to the method of data collection and operation of the system which result in an increased accuracy of determination of the absorption coefficients of nonpolar condensed gases. Typical results are given for the cells used in the temperature range from 126 to 410 K at pressures up to 1500 psi.