Knowledge Bank

The vibronic coupling expression for magnetic dipole interaction presented in the previous paper have been used to interpret the VCD spectra of molecules containing intramolecular rings closed by hydrogen bonding or metal ion coordination. The VCD intensities for a number of vibrational modes in these molecules cannot be adequately explained using VCD theories which employ approximate position dependent magnetic moment operators. For alanine and cobalt complexes of alanine and ethylene diamine, the lowest energy electronic transitions involve charge transfer between the hydrogen bonded or coordinated nuclei. The vibronic coupling terms due to these electronic transitions will be shown to generate contributions to the vibrational magnetic dipole transition moment of the proper sign.