Use of Solvents containing Ethyl Iodide in the Investigation of Phosphorescence Spectra of Organic Compounds

Abstract

M. KASHA¹ has suggested that the yellow colour produced when α-chloronaphthalene and ethyl iodide are mixed is due to the enhancement of the lowest singlet–triplet absorption band of the naphthalene molecule. He interpreted this effect in terms of a collisional perturbation of spin-orbital coupling in the aromatic molecule, by the heavy iodine atom. The singlet–triplet absorption bands reported for benzene by a number of workers² as well as those for a wide number of other aromatic molecules have been shown by Evans³ to be due to spin orbit perturbation by the inhomogeneous fields of dissolved paramagnetic oxygen molecules. The perturbing effects of ferric and cupric acetonyl acetonates have also been demonstrated⁴.