Infrared intensity analysis of CH₂Cl₂ and CD₂Cl₂ in vapour and liquid states

Abstract

In the infrared spectra of molecules with more than one C-H bond the symmetric and antisymmetric stretching bonds often overlap, causing uncertainty in the intensity analysis. For CH₂Cl₂ and CD₂Cl₂ in the vapour state, the two bands overlap to such an extent that Straley who takes it as one band attributes it to antisymmetric stretching while Saekiet al assign it to the symmetric stretching. Following the method of analysis initiated in this laboratory, we have solved this problem by ultimately obtaining intensities separately forA ₁ andB ₂ species. The band is mostly due to the symmetric stretching, 0.06 out of the total of 0.31 contributing toB ₂. Thus, this gives a method of separating the intensities of bands which are highly overlapping.