Knowledge Bank

The absolute in frared absorption intensities of the fundamental bands of some halogen derivatives of methane have been measured in the solid state at liquid nitrogen temperatures, using standard $techniques.1-3$ Comparison of the results with the intensities obtained for these bands in the gas phase reveals that the changes are relatively small, especially for derivatives which do not contain H atoms. Primarily, results for chloroform $(CC/3H)3$ and trichlorofluoro methane $(CC/3F)4$ will be presented. Here the C-H stretch in $CC/3H$ increases in intensity from gas to solid by a factor of $30,3$ while the corresponding C-F stretching vibration in $CC/2F$ changes only by a factor of 1.4. Other bands for both molecules show smaller changes (about a factor of 2). Financial support from the Army Research Office (Durham) and from Public Health Service Research Grant No. GM 14648 is gratefully acknowledge.