2021-10-24T14:04:38Zhttps://soar-ir.repo.nii.ac.jp/oaioai:soar-ir.repo.nii.ac.jp:000217152021-10-12T00:46:57Z1221:1222Ion-Conserving Modified Poisson-Boltzmann Theory Considering a Steric Effect in an ElectrolyteSugioka, HideyukiThe modified Poisson-Nernst-Planck (MPNP) and modified Poisson-Boltzmann (MPB) equations are well known as fundamental equations that consider a steric effect, which prevents unphysical ion concentrations. However, it is unclear whether they are equivalent or not. To clarify this problem, we propose an improved free energy formulation that considers a steric limit with an ion-conserving condition and successfully derive the ion-conserving modified Poisson-Boltzmann (IC-MPB) equations that are equivalent to the MPNP equations. Furthermore, we numerically examine the equivalence by comparing between the IC-MPB solutions obtained by the Newton method and the steady MPNP solutions obtained by the finite-element finite-volume method. A surprising aspect of our finding is that the MPB solutions are much different from the MPNP (IC-MPB) solutions in a confined space. We consider that our findings will significantly contribute to understanding the surface science between solids and liquids.ArticleJOURNAL OF THE PHYSICAL SOCIETY OF JAPAN.85(12):124006(2016)journal articlePHYSICAL SOC JAPAN2016-11-24application/pdfJOURNAL OF THE PHYSICAL SOCIETY OF JAPAN12851240060031-9015AA00704814https://soar-ir.repo.nii.ac.jp/record/21715/files/16K05650_09.pdfeng10.7566/JPSJ.85.124006https://doi.org/10.7566/JPSJ.85.124006© 2016 The Physical Society of Japan