Compression geometry

Fig. 2 a, b. A circular cross-section of the lower E e Jahn-Teller surface shown in Fig. 1 a without low symmetry terms - the three elongated octahedra correspond to the geometry at the three minima of the potential b with various degree of such that a tetragonally compressed geometry is ultimately stabilized... 

The positive slope of the Eg (Ty, Tg) split pair means that the excited state minima will tend to be at a compressed geometry. This means that Franck-Con-don factors will make the observation of transitions to the Eg (Ty, Tg) states difficult to observe from a tetragonally elongated ground state and they have not. 

One important application area is the derivation of the coefficient of thermal expansion (GTE). This is usually performed using tension or compression geometries and measuring the expansion although modern TMAs generally have the same range of deformation geometries as used by DMA, described in Section 4.3.2. 

Creep It is the processing of continuously changing length (or thickness for compression geometry) under an applied load. The deformation is time dependent, therefore yielding... 

Poisson s ratio It is defined as the ratio of lateral strain to longitudinal (lateral strain/longitudinal strain) in tension or compression geometry. 

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