Orientational behaviour of O2 molecules: interplay of van der Waals, quadrupole and magnetodipole interactions

Abstract

Orientational states for two molecules have been described, which are caused by van der Waals, quadrupole-quadrupole, and magnetodipole (or electric dipoledipole) interactions, their competition giving rise to three phases, with parallel-perpendicular (T-like phase I), inclined (phase II), and parallel (phase III) molecular configurations relative to the line connecting molecular centres. For weak dipoldipole interactions, the three phases change with increasing intermolecular distance (from the intermolecular repulsion radius on) in the order: III-II-I-II-III. As revealed for the O2 molecules, the phase I vanishes and the phase II results in the range of 6.78 to 43.3 A°.