Electro-Optical Kerr Effect in Gases

The Kerr constant B of CO₂ has been measured as a function of density from 0.06 to 0.32 g/cm³ and as a function of temperature from 7.2 to 34.6^∘{}C. The results are in agreement with the Langevin-Born theory. The absolute value of B for CO₂ has been measured and is 0.34×{}10^-10 per atmosphere for wave-length 4550A and temperature 34.6^∘{}C. This is also the theoretical value of B for CO₂. The probable error of the measured value is 2 percent. The absolute value of B for N₂ measured by comparison with CO₂ is 0.057×{}10^-10 for the above wave-length and temperature, with a probable error of 3 percent. The corresponding theoretical value for N₂ is 0.050×{}10^-10. The Kerr constant of H₂ is shown to be less than 0.01×{}10^-10 which is not in disagreement with the theoretical value of 0.005×{}10^-10.