Separation of translation and rotation

Multiangle Measurements. More information is potentially available from multiangle measurements. Zero-angle extrapolated data are more amenable to proper data transformation. Separation of translational and rotational motion of highly acicular particles is possible. Verification of peaks at more than one angle lends credence to their existence. Simultaneous deconvolution of angular data may provide a useful constraint. 

There is no simple method or computer code for treating coupled vibrational modes in polyatomics. One of the problems is the separation of translation and rotation from the general nuclear motion. This route was always taken in the conventional method (Eckard-Wilson-Watson formalism) in the precomputer era. It is conceivable that in computational approaches variational calculations are more efficient than the earlier Taylor expansion and perturbation approaches, which try to formulate the problem as far as possible in analytical terms an excellent survey is given by Sutcliffe. ... 

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