  A generalized notion of a nonlocal tensor order parameter is introduced
within the framework of the phenomenological approach. This parameter has the
form of a traceless tensor correlation function or a tensor integral operator.
Based on this form, the governing relations are written, which determine the
steady states and phase transitions of the deformed liquid crystal. Linear
relations for eigenfunctions of the introduced operator are derived. A
principal drawback of currently available models of liquid crystals based on
the local presentation of the tensor order parameter (equality of two Frank
constants in the case of a quadratic form of the strain part of the free
energy) is eliminated. Particular examples are considered, which demonstrate
the model workability and the absence of contradictions in the model as well as
its adequacy when describing small-scale structures.
