A group additivity rule for integrated band strengths of the C—H chromophore in the infrared
Abstract
Integrated band strengths are reported for the C—H stretching fundamental transition near 3000 cm–1 in the i.r. vapour-phase spectra of nine saturated fluorohydrocarbon molecules of general formula CkFlClmH. The nature of the absorption of the C—H chromophore is discussed in terms of conservation of the band strength G when coupling the chromophore states to optically inactive background states and in terms of the local electronic environment of the C—H group. The values of G are found to be well approximated by a three-parameter group additivity rule.