Sound Absorption in the Halogen Gases Available to Purchase

Apparatus has been constructed for measuring sound absorption by the tube method in corrosive gases at high temperatures. This apparatus has been used to measure sound absorption in chlorine, bromine, and iodine vapors at temperatures between 25 and 256°C. The measurements revealed vibrational relaxation absorption peaks in all the gases. In $Cl2$ the relaxation times varied from 4.90 μsec at 25°C to 1.55 μsec at 255°C. In $Br2$ the variation was from 0.854 μsec at 28°C to 0.460 μsec at 256°C. In $I2$ the relaxation time was almost independent of temperature, changing only from 0.106 to 0.102 μsec when the temperature changed from 112 to 253°C.

The heights of the absorption peaks were adequately predicted by assuming the relaxing vibrational specific heat to be $Cp−72R$⁠. Neither the Schwartz‐Herzfeld nor Cottrell‐Ream theoretical equations for the relaxation time accurately predict the measured variation with temperature, molecular mass and vibrational frequency.