Molecular complexes and their spectra. VI. Some problems and new developments

Although the charge‐transfer theory probably affords a correct general account of major aspects of the structure and spectra of molecular complexes, its application to the detailed structures of particular types of complex presents a variety of problems whose definitive solution will require much new experimental and theoretical research, but should then yield many interesting conclusions. The effects of London dispersion forces and classical electrostatic forces as well as charge‐transfer forces must always be taken into account. Orientation isomerism, acceptation cross‐sections of acceptor molecules, paraffin‐halogen interactions and their contact charge‐transfer spectra, intensity problems, the blue shift of the iodine visible band in the spectra of iodine complexes, and complexes with two charge‐transfer spectra, are discussed below.