The singularities of the quantum-mechanical electron current density induced in a molecule by an external magnetic field are analyzed via the theory of the real autonomous systems of differential equations. Group-theoretical techniques, based on the idea of color symmetry, are developed, which predict the occurrence of singularities about molecular symmetry elements. Plots of induced electron current density have been obtained for the ethylene molecule through accurate coupled SCF calculations. The theoretical magnetic properties of ethylene obtained through this investigation are the most accurate reported so far.
Singularities of Magnetic-Field Induced Electronic Current Density: A Study of the Ethylene Molecule / Lazzeretti, Paolo; E., Rossi; R., Zanasi. - In: INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY. - ISSN 0020-7608. - STAMPA. - 25:(1984), pp. 929-940.