TITLE

Entropy-enthalpy compensation: Perturbation and relaxation in thermodynamic systems

AUTHOR(S)
Qian, Hong; Hopfield, J. J.
PUB. DATE
November 1996
SOURCE
Journal of Chemical Physics;11/22/1996, Vol. 105 Issue 20, p9292
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The response of an equilibrium molecular system to perturbations depends on its environmental constraints. For example, the response of an equilibrium P, V, T system to a small temperature perturbation (specific heat) depends on whether the environmental constraint on the system is constant pressure or constant volume. In general, there are two classes of thermodynamic quantities of a system; one is completely determined by its equilibrium distribution, and the other also depends on how the distribution responds to macroscopic changes. The former class is independent of the environment of the thermodynamic system, while the latter class is a function of environmental constraints. In response to a small perturbation, the free energy change of an equilibrium system belongs to the first class but the entropy and enthalpy changes belong to the second. Therefore the thermodynamics of perturbation exhibit compensation between entropy and enthalpy of systems with different environments. The thermodynamic analysis presented here provides a framework for the interpretation of experimental observations of this phenomenon, and is illustrated by a real experimental example. © 1996 American Institute of Physics.
ACCESSION #
7639823

 

Related Articles

  • Compressive stress relaxation through buckling of a low-k polymer-thin cap layer system. Iacopi, F.; Brongersma, S. H.; Maex, K. // Applied Physics Letters;3/3/2003, Vol. 82 Issue 9, p1380 

    The thermomechanical stability of a system composed of a metallic cap layer on top of a low-k thermosetting polymer film is investigated. It is observed that, when metal layers with high compressive stresses are used, a stress relaxation takes place during thermal anneal at temperatures above...

  • Calculation of enthalpy and entropy differences of near-critical binary mixtures with the modified Leung–Griffiths model. Rainwater, James C.; Friend, Daniel G. // Journal of Chemical Physics;2/1/1993, Vol. 98 Issue 3, p2298 

    In previous applications of the Leung–Griffiths model as modified by Moldover and Rainwater, many near-critical vapor–liquid equilibrium surfaces have been described successfully in the space of pressure, temperature, density, and composition, but calorimetric properties such as...

  • An efficient approach to estimating thermodynamic properties of fluid mixtures in molecular simulation. Wu, Xiong-Wu; Sung, Shen-Shu // Journal of Chemical Physics;3/8/1996, Vol. 104 Issue 10, p3709 

    To efficiently estimate the composition-dependent thermodynamic properties of fluid mixtures by molecular simulation, a method that adopts a thermodynamic path along a composition profile was proposed. In this method the relative values of both entropy-related properties, such as free energy,...

  • The Features of Vacancy Formation at Low Temperatures. Magomedov, M. N. // Technical Physics Letters;Sep2001, Vol. 27 Issue 9, p773 

    Expressions for the calculation of the thermodynamic potential, enthalpy, entropy s[sub v], and volume of vacancy formation in a simple crystal at temperatures close to absolute zero are derived. It is established that the vacancy concentration φ as a function of the temperature T exhibits a...

  • Comparison of enthalpy relaxation between two different molecular masses of a bisphenol-A polycarbonate. Lee-Sullivan, Pearl; Bettle, M. // Journal of Thermal Analysis & Calorimetry;Jul2005, Vol. 81 Issue 1, p169 

    The present work is an extension of an earlier study that compared the stress relaxation between two molecular masses of a bisphenol-A polycarbonate due to thermal aging. The enthalpy relaxation of the same materials has been characterized. First, by measuring the change in enthalpy loss (Δ...

  • Thermodynamics of calcium uranosilicate. Chernorukov, N. G.; Knyazev, A. V.; Sheiman, M. S.; Ponomarev, S. S.; Gur'eva, T. A. // Radiochemistry;May2006, Vol. 48 Issue 3, p240 

    The standard enthalpy of formation at 298.15 K of crystalline α-Ca(HSiUO6)2 · 5H2O (−6781.0 ± 9.5 kJ mol−1) was determined by reaction calorimetry. The heat capacity in the range of 80–300 K was measured by adiabatic vacuum calorimetry, and the thermodynamic functions...

  • Thermodynamics of lutetium uranosilicate. Chernorukov, N. G.; Knyazev, A. V.; Sheiman, M. S.; Ponomarev, S. C.; Gur'eva, T. A. // Radiochemistry;Sep2006, Vol. 48 Issue 5, p437 

    The standard enthalpy of formation of crystalline Lu(HSiUO6)3 � 10H2O at 298.15 K, -10668.0�16.0 kJ mol-1, and the standard enthalpy of its dehydration were determined by reaction calorimetry. The heat capacity of this compound in the range 80�300 K was measured by adiabatic...

  • Heat capacities and absolute entropies of UTi2O6 and CeTi2O6. Donaldson, Marcus H.; Stevens, Rebecca; Lang, Brian E.; Boerio-Goates, Juliana; Woodfielda, Brian F.; Putnam, Robert L.; Navrotsky, Alexandra // Journal of Thermal Analysis & Calorimetry;Sep2005, Vol. 81 Issue 3, p617 

    As part of a larger study of the physical properties of potential ceramic hosts for nuclear wastes, we report the molar heat capacity of brannerite (UTi2O6) and its cerium analog (CeTi2O6) from 10 to 400 K using an adiabatic calorimeter. At 298.15 K the standard molar heat capacities are...

  • Statistical thermodynamics of electrons and holes in semiconductors. Gokcen, N. A. // Journal of Chemical Physics;8/1/1985, Vol. 83 Issue 3, p1240 

    A statistical thermodynamic treatment is presented for the formation of electrons and holes in nondegenerate semiconductors, and for the accompanying standard changes in the Gibbs energy ΔG°, entropy ΔS°, heat capacity ΔC°, and enthalpy ΔH°. The treatment leads to the...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics