Adiabatic behavior, quasi

As an independent experiment to verify the findings of the TDBS we also performed quasi adiabatic measurements of the specific heat capacity Cp (74) using modulated differential scanning calorimetry (N SC) (20-22). Usually the glass transition is characterized by a step like behavior of Cp(T). The thermal glass transition... 

When the quadratic coupling terms in Eq. (3) are included, the rotational symmetry of the potential surfaces in Eq. (4) is lost and replaced by a threefold symmetry inherent to systems with a threefold rotation axis. Consequently, j ceases to be a good quantum number and the spectra of the linear E e JT system for individual j become mixed . This inherently two-dimensional vibronic motion leads to a complicated, erratic line structure (see, for example, Ref. 21) as is typical for other, less symmetric conical intersections discussed throughout this book. The above statements about adiabatic and nonadiabatic behavior for i < 0 and E > 0, and the formation of broad quasi-resonances arising from the upper cone vibrational levels, are not affected by the inclusion of quadratic coupling terms. 

For simple analytical adiabatic channel model potentials one can derive simple analytical expressions for the transmission coefficients. Often, one may replace 7a by the crudest quasi-classical model, giving a step function behavior with the Heaviside function h x > 0) = 1 and h x < 0) = 0 in equation (53) ... 

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