Abstract

The definition and actual determination of orientational and positional order parameters plays a key role in describing the variety of molecular organizations of liquid crystals and in quantifying their changes, e.g. at phase transitions or when approaching an interface. The classical description of order in terms of a single parameter, which implicitly assumes a simple rigid and uniaxial molecular shape, has to be refined in a number of ways, e.g. to allow for biaxiality [1] or internal flexibility [2,3] or inhomogeneities in thin films [4] or nanodroplets [5]. This increased complication has become essential in view of progresses in experimental and simulation techniques, now offering an unprecedented level of detail and of possibilities of putting theories of liquid crystals and ultimately our understanding of anisotropic phases to the test. In the talk we present some examples of order and structure determinations from coarse grained [1,5] and atomistic simulations [2-4].