Basics of Melting and Glass Formation

Hoffmann, Hans‐Jürgen

doi:10.1007/978-1-4419-0736-3_8

Cited by 2 publications

(2 citation statements)

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“…The mixed different states of each oscillator couple to and modify the electronic states and their wave functions. All of these effects can be seen experimentally and be explained by the interaction of the excited vibrations or phonon states with the wave functions of the bonding electrons (see also [, , , ]). If at still increasing temperatures more and more electrons are transferred to states with higher energy, such as in a melt, an additional contribution to the thermal expansion occurs, as wave functions belong to excited states and not only to ground states.…”

Section: Entropymentioning

confidence: 99%

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Entropy and entropy of mixing

Hoffmann

2014

Materialwissenschaft Werkst

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Entropy as a function of temperature at constant volume, S(T), can be determined by integrating the molar specific entropy capacity CV/T (CV: molar specific heat capacity at constant volume). As a second approach, S(T) at constant volume can be determined by differentiating the free energy with respect to the temperature, T. Recently, it has been shown for a system obeying Boltzmann statistics that these mathematical approaches are equivalent to applying the formula of the mixing entropy, if the ground and excited states of the same sub‐systems or elementary systems are considered as mixing objects or quantum components. This result considerably extends the applicability of the formula of the mixing entropy, which is derived in textbooks just for mixing real indifferent components. In the present paper, it is shown that the formula of the mixing entropy can also be applied to calculate the entropy of Bose and Fermi systems. Thus, all entropy can be calculated and interpreted as mixing entropy of real components or quantum components. In reverse, the transitions between the ground and the excited states of any system can be explained as mixing processes. This interpretation is applied to the melting transition of chemically bonded solids and in particular to the glass transition whereby upon cooling the mixing entropy of the melt is (at least partly) frozen in the configuration. These results suggest a new interpretation of the glass transition and a new definition of structural glass.

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Section: Entropymentioning

confidence: 99%

“…This is supported by the vibrations since the excited electrons and holes interact with the core ions and modify the parameters of the vibrations. Thus, melting is induced by the interaction of electrons in excited states with the core ions and with different phonon states of the vibrations (see also [, , , ]).…”

Section: Entropymentioning

confidence: 99%