Time-dependent molecular fields created by the interaction of an external electro-magnetic field with a molecular system: the derivation of the wave equations.

This article continues a previous study (Int. J. Quantum Chem.114, 1645 (2014)) in which is presented a theory that discusses the possibility to induce a novel field – to be called molecular field – via the interaction of an external electro-magnetic (EM) field and a molecular system. Assuming the molecular system is made up of two coupled adiabatic states the theory leads from three time-space curl equations and one time-space divergence equation to a set of decoupled wave equations usually encountered for fields. In the present study, wave equations are derived for an external field having two features: (1) the field intensity is relativelyhigh enough; (2) the duration of the interaction isshort enough. For this situation, the study reveals that the just mentioned interaction creates two fields that coexist within a molecule: one is just a scalar EM field essentially identical to the external EM field and the other, a vectorial field, produced by the non-adiabatic coupling terms. In addition, we mention that the wave velocities related to these two fields are identical to the wave velocity, c, of the external EM field. [ABSTRACT FROM PUBLISHER]