% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@INPROCEEDINGS{Janotta:1046349,
      author       = {Janotta, Benjamin and Schalenbach, Maximilian and Tempel,
                      Hermann and Eichel, Rüdiger-A.},
      title        = {{I}nconsistencies in the {D}ebye-{H}ückel theory related
                      to the {S}tatistic {F}oundation and {P}ermittivity},
      reportid     = {FZJ-2025-03778},
      pages        = {1},
      year         = {2025},
      abstract     = {The Debye-Hückel (DH) theory, a cornerstone in modeling
                      ionic activities in electrolytes for over a century, remains
                      widely applied like in equations of state and Onsager’s
                      conductivity theory1. In the DH theory, the distribution of
                      ions around a central ion is calculated assuming
                      electrostatic interactions of point charges that are
                      dispersed in a dielectric continuum2. To date, the
                      parameterization of the DH theory is still being
                      investigated, especially regarding the integration of the
                      concentration-dependence of the relative static permittivity
                      (dielectric constant), to improve the predictive
                      capabilities of models3,4,5. In this presentation, we show
                      that the theoretical foundation of the electrostatic
                      interactions, namely the employed Poisson-Boltzmann
                      framework, violates the statistical independence of states
                      presumed for the Boltzmann theory. Hence, the
                      physicochemical rigorosity of the DH theory is more
                      restricted than often assumed in contemporary literature1.
                      Even the DH limiting law, which is believed to be the most
                      rigorous DH model, is subjected to this inconsistency.
                      Additionally, the relative static permittivity of
                      electrolytic solutions is critically examined, revealing
                      inaccuracies in conventional extraction methods from
                      experimental data obtained by dielectric spectroscopy.
                      Consequently, the static permittivities of electrolytes and
                      their concentration-dependences are subjected to
                      unquantified uncertainties. To assess the impact of the
                      uncertainties discussed, a sensitivity analysis demonstrates
                      how a variation in the permittivity is overshadowed by
                      adjusting the usual fitting parameters, the ionic radii, and
                      arbitrary combinations of model extensions (such as models
                      for the hard sphere contribution, Born term, and
                      association). Ultimately, this presentation emphasizes that
                      the theoretical foundations of the DH theory are fragile,
                      restricting its applicability to fitting experimental data
                      rather than enhancing predictive models. 6References:[1] G.
                      M. Kontogeorgis, B. Maribo-Mogensen and K. Thomsen, Fluid
                      Phase Equilibria, 2018, 462, 130–152.[2] P. Debye and E.
                      Huckel, Phys Z, 1923, 24, 185–206. [3] G. M. Silva, X.
                      Liang and G. M. Kontogeorgis, Fluid Phase, Equilibria, 2023,
                      566, 113671. [4] Rueben, P. Rehner, J. Gross and A. Bardow,
                      Journal of Chemical $\&$ Engineering Data, 2024, 69,
                      3044–3054. [5] I. Y. Shilov and A. K. Lyashchenko, Journal
                      of Solution Chemistry, 2019, 48, 234–247.[6] B. Janotta,
                      M. Schalenbach, H. Tempel, R.-A. Eichel, Physical Chemistry
                      Chemical Physics, 2025, DOI: 10.1039/D5CP00646E},
      month         = {Sep},
      date          = {2025-09-07},
      organization  = {76th Annual Meeting of the
                       International Society of
                       Electrochemistry, Mainz (Germany), 7
                       Sep 2025 - 12 Sep 2025},
      cin          = {IET-1},
      cid          = {I:(DE-Juel1)IET-1-20110218},
      pnm          = {1231 - Electrochemistry for Hydrogen (POF4-123) / PRELUDE -
                      Verbundvorhaben PRELUDE: Prozess- und Meerwasser-Elektrolyse
                      für eine umweltverträgliche Grüne Wasserstoffwirtschaft
                      in Deutschland (BMBF-03SF0650A) / HITEC - Helmholtz
                      Interdisciplinary Doctoral Training in Energy and Climate
                      Research (HITEC) (HITEC-20170406)},
      pid          = {G:(DE-HGF)POF4-1231 / G:(DE-Juel1)BMBF-03SF0650A /
                      G:(DE-Juel1)HITEC-20170406},
      typ          = {PUB:(DE-HGF)8},
      url          = {https://juser.fz-juelich.de/record/1046349},
}