Email: zhonghanhu_ATA_email._sdu._edu._cn (Please remove _ and change ATA to @)
Research Description:
Statistical mechanics relates macro and mesoscopic observations, either in a real experiment or in an artificial numerical simulation, to microscopic interactions and dynamics. In order to make such a relation powerful and predictive, one may introduce certain approximations to simplify the statistical formulations in the framework. The symmetrypreserving meanfield (SPMF) approximation that I am primarily working on [1] follows the meanfield ideas by Johannes van der Waals, Benjamin Widom, and John Weeks, which split the total microscopic interaction into the shortranged rapidly varying and longranged slowly varying components and then treat them separately. The SPMF approach further suggests that certain slowly varying component can be replaced by its average over the degrees of the freedom with preserved symmetry[1,2].
This approach naturally leads to accurate and efficient methods for numerical simulations of condensed phases by using the known symmetries and boundary conditions as guiding constrains. Given the clear physical picture of a problem, the meanfield approach may even provides simple, intuitive and transparent understanding of the underlying mechanism.
As a particular example, SPMF has been applied to the problem of proper treatments of electrostatics in molecular simulations[3,4]. When the lattice sum formulation (e.g. Ewald sums [5,6,7]) for electrostatics under periodic boundary conditions are formulated as a pairwise interaction[8,9], the difference between the defined pairwise interaction and the Coulomb interaction is regarded as a slowly varying components. Under the spherical symmetry, the average effect of this slowly varying component vanishes, which therefore justifies the use of the Ewald sum method with tinfoil boundary condition for simulations of bulk and spherical interfaces[3]. On the other hand, corrections are necessary when charges or polar molecules are placed on planar walls[3,4]. In addition, when the dielectric constant is sufficient to describe the response of the dielectric material to an external electric field or a charged wall, the meanfield theory predicts analytically the finitesize effect in supercell modelling of charged interfaces, which was confirmed by the numerical simulations in the literature[4].
Representative Publications:
[1].Zhonghan Hu (2014) “Symmetrypreserving mean field theory for electrostatics at interfaces” Chem. Commun. 50, 14397
[2]. Shasha Yi; Cong Pan; Liming Hu; and Zhonghan Hu (2017) “On the connections and differences among three meanfield approximations: a stringent test”, Phys. Chem. Chem. Phys. 19, 18514
[3]. Cong Pan; Shasha Yi; and Zhonghan Hu (2017) “The Effect of electrostatic boundaries in molecular simulations: symmetry matters”, Phys. Chem. Chem. Phys. 19, 4861
[4]. Cong Pan; Shasha Yi; and Zhonghan Hu (2019) “Analytic theory of finitesize effects in supercell modelings of charged interfaces”, Phys. Chem. Chem. Phys. 21, 14858
[5]. Shasha Yi; Cong Pan; and Zhonghan Hu (2015) “Accurate treatments of electrostatics for computer simulations of biological systems: A brief survey ofdevelopments and existing problems” Chin. Phys. B, 24, 120201
[6]. Cong Pan; and Zhonghan Hu (2014) “Rigorous Error Bounds for Ewald Summation of Electrostatics at Planar Interfaces”, J. Chem. Theory Comput. 10, 534
[7]. Cong Pan; and Zhonghan Hu (2015) “Optimized Ewald sum for electrostatics in molecular selfassembly systems at interfaces” Sci. China Chem. 58, 1044
[8]. Zhonghan Hu (2014) “Infinite boundary terms of Ewald sums and pairwise interactions for electrostatics in bulk and at interfaces”, J. Chem. Theory Comput. 10, 5254
[9]. Shasha Yi; Cong Pan; and Zhonghan Hu (2017) “Note: A pairwise form of the Ewald sum for nonneutral systems”, J. Chem. Phys., 147,126101
A Full List of Publications:
https://orcid.org/0000000348792775
https://publons.com/researcher/2768853/zhonghanhu
Group Members:
Time 
Name 
Education 
Current Position 
2011.9  2017.9 
Cong PAN 
Ph.D 
Postdoc at Hongkong Univ. Sci. & Tech 
2012.9  2017.12 
Shasha YI 
Ph.D 
Postdoc at Peking Univ 
2014.9  2017.9 
Liming HU 
Master 
HUAWEI Beijing Institute 
2012.9  2014.9 
Wenmei GAO 
Master 
Ass. Prof. at Shanxi Normal University 
2018.9  2019.9 
Weihang GAO 
U.Grad. 
Ph.D student at Shanghai Jiaotong University
