Infrared absorption spectrum of carbon disulfide.

The infrared absorption spectrum of carbon disulfide has been remeasured in the region from 2 to 24 I' with cells up to 5 mm in t hickness. Fifteen bands were observed , some however being of low intensity. The strongest band for the liquid occurs at 6.621' , and t he second harmonic of this band was observed at 2.22 1' , but t he first harm onic, which should be at about 3.33 1' , was not observed, in accordance with the selection rules for a symmetrical linear molecule. Four combination bands were observed between 3 and 5 1' , whose wavelengths " 'ere in good agreement with the calculated values. A combination band , which is represented by the difference between t wo fundam entals, occurs a s a broad, moderately st.rong band in t he region of 11.61'. A weak band, observed at 15.271-'< corresponds with the wavelength of t he inactive vibration of the molecule. However, when t his region was t udied with a 140 cm cell filled with the saturated vapor of C82 at room temperature, no baml was observed . In the vapor state a total of six bands were found at wavele,1gths less than 201' . The fund amental band at 6.5 I' shows a side branch that is probably due to t he isotopic effect produced by C13. 80me small bands t hat were observed may be attribu ted to the 02832834 molecule. As would be expected for t his molecular configuration , the spectrum of C82 as observed may be classified into an array of terms analogous to those of CO2• A band at 12.7 I' has different intensi ties for samples obtained from two differen t sources and may be caused by an impurity. This band did not appear when the cell containing the vapor was