Peculiarities in the director reorientation and evolution of NMR spectra under the influence of crossed electric and magnetic fields

Theoretical description is proposed for new modes of reorientation of the director field $\mathbf{\hat n}$ and the evolution of the NMR spectrum $I(\nu)$ of a nematic liquid crystal (LC) formed by molecules of deuterated 4-n-pentyl-4'-cyanobiphenyl encapsulated in a rectangular LC cell under the action of crossed electric, $\mathbf{E}$, and magnetic, $\mathbf{B}$, fields directed at an angle of $\alpha$ to one another. Numerical calculations in the framework of the nonlinear generalization of the classical Ericksen–Leslie theory show that, under certain relations between the forces and moments acting upon a unit volume of the LC phase upon the reorientation of $\mathbf{\hat n}$, transient periodic structures can arise if the corresponding distortion mode is characterized by the fastest response and thus suppresses all other modes, including uniform ones. It is shown that the rise of these periodic structures leads to a reduction in the time for the reorientation of the director field.